Since the 1953 armistice that stopped active fighting in the Korean War, the U.S. military has maintained dozens of military bases and tens of thousands of troops in South Korea. Currently, there are 80 U.S. military base sites in the country and around 27,000 troops and civilian military personnel.[1]
There is no comprehensive, publicly available accounting of annual U.S. taxpayer spending to maintain military bases, troops, and weaponry in South Korea. Many appear to have underestimated these costs, sometimes significantly, for years.
Some, for example, have wrongly assumed that maintaining U.S. bases and troops in the Republic of Korea (ROK) is effectively “free” for U.S. taxpayers because the South Korean government pays some of the costs. For example, during congressional testimony in 2016 that was widely reported in the media, General Vincent Brooks incorrectly asserted that it is “absolutely” more expensive to keep “troops stationed in the United States than it would be in Korea.”[2]
This is false.
Even when countries like South Korea cover some of the costs of maintaining U.S. troops and bases abroad, as South Korea does, U.S. taxpayers pay significantly more to keep troops overseas compared to stationing in the United States. On average, taxpayers pay around $14,500 to $58,000 more per person annually to station military personnel abroad, according to the best available analysis. In South Korea, the military spends, on average, $24,700 more per person in the Army and $25,380 more per person in the Air Force compared to annual costs at comparable bases in the continental United States.[3] The costs of transportation, the higher cost of living in countries like South Korea, and the expense of providing hospitals, housing, schools, and other supports to military personnel and family members of personnel abroad all contribute to the extra expense.[4]
This report builds on the best publicly available data to provide a more comprehensive accounting of what U.S. taxpayers actually spend to maintain U.S. bases and troops in South Korea. Unfortunately, an exact calculation is impossible given a lack of Pentagon budget transparency and the Pentagon’s inability to track and audit its own spending.[5]
Using data from the Government Accountability Office, the Congressional Budget Office, and the Pentagon, this report concludes that after one subtracts the value of direct payments and in-kind contributions made by the South Korean government, the U.S. government and U.S. taxpayers currently spend around $5.5 billion to $6 billion to maintain U.S. bases and troops in South Korea. The precise figure for fiscal year 2024 was $5,579,509,616 ($5.58 billion), which is almost $2.19 billion more than what the Pentagon has reported.
Given the unreliable nature of Pentagon accounting practices, this calculation may significantly underestimate some costs. The true total may exceed $6 billion annually.
Table 1: Costs of U.S. Military Bases and Troops in South Korea (ROK)
| YEAR | U.S. COSTS AS PER GAO/OCS ESTIMATES[6] | TOTAL ROK CONTRIBUTIONS[7] | ADDITIONAL U.S. COSTS IDENTIFIED | REVISED U.S. COST ESTIMATES |
| 2016 | $3.12 billion | ($1.20 billion) | $2.23 billion | $4.15 billion |
| 2017 | $3.34 billion | ($1.74 billion) | $1.88 billion | $3.48 billion |
| 2018 | $3.53 billion | ($1.30 billion) | $2.67 billion | $4.90 billion |
| 2019 | $3.38 billion | ($1.52 billion) | $2.48 billion | $4.33 billion |
| 2020 | $3.60 billion | ($1.24 billion) | $2.03 billion | $4.39 billion |
| 2021 | $3.70 billion | ($1.30 billion) | $1.75 billion | $4.15 billion |
| 2022 | $3.94 billion | ($1.05 billion) | $2.00 billion | $4.88 billion |
| 2023 | $4.10 billion | ($1.23 billion) | $1.94 billion | $4.80 billion |
| 2024 | $4.26 billion | ($.87 billion) | $2.19 billion | $5.58 billion |
Figures in current year U.S. dollars. Numbers may not sum due to rounding. The years 2016–2019 are calendar years, following the main data source for those years, the Government Accountability Office. The years 2020–2024 fiscal years, following the main data source, the Pentagon’s “Overseas Cost Summary.”
Background
Since the onset of the Korean War in 1950, the U.S. government—and U.S. taxpayers—have expended tens of billions of dollars to maintain bases and troops in South Korea. Amid the rapidly growing wealth of South Korea and the fall of the Soviet Union, the U.S. government negotiated to require the South Korean government to begin making direct payments to assume some of the costs associated with maintaining the U.S. military in the country (as in other countries hosting U.S. bases and troops, such as Germany, Japan, and Kuwait).
This arrangement began in 1991. Since that time, the amount the South Korean government and South Korean taxpayers have paid through direct cash transfers and in-kind contributions (such as construction) has been a matter of diplomatic negotiation and public debate. In 2018 President Donald Trump demanded $5 billion annually from South Korea—around 400% higher than prior payments—to cover the U.S. military’s costs.[8] Many observers suggested this figure was a negotiating tactic to pressure the South Korean government into higher payments. A Pentagon report submitted annually to Congress, the “Overseas Cost Summary” (or “Overseas Cost Report”), showed actual spending of around $3.3 billion in fiscal year (FY) 2017, with proposed spending for FY2019 of $3.5 billion.[9]
These debates continued as the two governments renegotiated the terms of South Korea’s payments across the transfer of power from the Trump administration to President Joe Biden’s presidency. In this context, the Government Accountability Office (GAO) published a 2021 report estimating costs of between $3.2 billion and $3.6 billion per year between FY 2016 and FY2019, based on data provided by the armed forces. The GAO also calculated South Korean payments of between $1.2 billion and $1.7 billion in the same time period.[10] This suggested net U.S. costs of between $1.6 billion and $2.2 billion annually.[11]
A New Estimate
This report addresses omissions in both the GAO report and the Pentagon’s congressionally mandated “Overseas Cost Summary” (OCS), which differ in their calculations by nearly $1 billion at times.[12] Surveying the years 2016 to 2024, this report estimates that the net cost of U.S. bases and troops in South Korea, subtracting South Korean contributions to support the U.S. presence, ranged from $3.482 billion (at its lowest in FY2017) to $5.580 billion (in 2024).
For perspective, $3.482 billion, alone, would be enough to pay for around 78,000 four-year college scholarships, fund around 193,200 military veterans receiving Veterans Administration medical care for a year, or hire around 19,400 registered nurses or 39,300 elementary school teachers for one year.[13]
This report’s calculations may be a significant underestimate given costs that this report is unable to estimate reliably and several forms of additional spending outlined below. Any omitted costs could add tens or hundreds of millions in additional spending. Unfortunately, because of limited Pentagon transparency and the Pentagon’s inability to accurately track and report its spending,[14] a precise, fully comprehensive calculation of U.S. spending in South Korea (or in any country where the Pentagon operates) is currently impossible.
Cost Data: The Government Accountability Office and “Overseas Cost Summary”
The best available sources of data on U.S. military spending in South Korea are the GAO’s 2021 report “Burden Sharing: Benefits and Costs Associated with the U.S. Military Presence in Japan and South Korea” and the Pentagon’s annual OCS report. While this report relies on the two for the calculations below, both provide limited, incomplete, or unreliable data. The basic problem underlying both reports is their reliance on spending data from an organization, the Pentagon, with a well-documented inability to track its own spending and pass a financial audit. Congress first ordered the Pentagon to make itself auditable in 1997; the Pentagon remains the only federal agency never to have passed an audit.[15]
GAO “Burden Sharing” Report
The GAO “Burden Sharing” report, which the agency produced at Congress’s request, appears more authoritative than the OCS given the GAO’s carefully documented methodology and overall reputation for reliable, rigorous research. For fiscal years 2016–2019, the report relies on the GAO’s report, which covers the same calendar years.[16] For FY2020–2024, the report was forced to rely on OCS data for South Korea as the basis for its calculation.
The GAO report has limitations due to the GAO’s reliance on data provided by the four branches of the armed forces, which share accounting problems with the larger Pentagon bureaucracy. To start, the data provided by the branches come from several different financial tracking systems (three in the Navy alone). In some cases, the armed forces could not provide data by calendar year or by quarter, forcing the GAO to make calculations by adjusting fiscal year data.[17] The branches also appear to have provided GAO with incomplete or unreliable data for at least personnel costs, military construction, and family housing construction, as explained below.
Pentagon “Overseas Cost Summary” Report
The Pentagon’s OCS report is an example of some of the larger problems afflicting the military’s financial tracking: In theory the report should answer the question of how much the U.S. government spends on bases and troops in South Korea. By law, Congress requires the Pentagon to produce the OCS annually to report what the Pentagon spends on all the military’s activities at bases, embassies, and other facilities abroad.[18] This means calculating all the costs of building, running, and maintaining every base site, garrison, airfield, port, warehouse, ammunition dump, radar station, and drone base, plus the costs of paying for and maintaining every military personnel and family member abroad, including all their salaries, housing, schools, teachers, hospitals, moving costs, lawn mowing, utilities, and much more.
In practice, the report frequently omits data and provides data of limited reliability. In some cases, the OCS omits spending in countries entirely or indicates spending at levels that are clearly erroneous or at least misleading. For example, the FY2021, FY2022, and FY2023 OCS reports indicated spending of $1 million in a country like Niger, where the military operated multiple bases until 2024, including one that cost U.S. taxpayers at least $100 million to build.[19] (OCS regulations allow the Pentagon to exclude the costs of bases, personnel, and activities that are not performed on a “permanent” basis.[20] For political and diplomatic reasons, the Pentagon frequently depicts bases and troops abroad as “temporary” in nature. A more than forty-year-old “temporary” base in Honduras shows how the Pentagon can destroy the meaning of such terms.)[21]
In other cases, the OCS dramatically understates costs. At times the OCS reports spending on troops’ salaries but no money for “operation and maintenance.” This would mean not having funds to turn the lights on, feed people, or do regular repairs. In other countries where thousands of troops are working, the OCS reports no spending to pay personnel. In some cases, the OCS indicates $0 in operation and maintenance, military personnel, and military construction spending. Clearly the report either omits the relevant figures or the military did not gather the necessary data.[22]
In addition to bureaucratic and financial tracking problems being at fault for the OCS’s unreliable data, political manipulation is also likely to blame. A prime example appears in spending levels reported for South Korea: after President Trump began demanding annual payments of $5 billion from the country, U.S. costs in South Korea jumped by more than $3 billion between FY2019 and FY2020 OCS submissions.
With the limitations of the OCS and GAO reports noted, this report uses their data as the initial basis for its calculations. The report subtracts the South Korean government’s direct financial payments and in-kind contributions using GAO data (2016–2019) and data reported in other Pentagon budget materials (2020–2024).
Table 2: Prior Estimates of the Costs of U.S. Bases and Troops in South Korea
| YEAR | PRIOR ESTIMATES OF U.S. COSTS[23] | TOTAL ROK CONTRIBUTIONS[24] | PRIOR ESTIMATES OF NET U.S. COSTS |
| 2016 | $3,122,000,000 | ($1,202,226,615) | $1,919,318,136 |
| 2017 | $3,342,000,000 | ($1,738,312,122) | $1,603,843,975 |
| 2018 | $3,530,000,000 | ($1,304,149,724) | $2,226,217,014 |
| 2019 | $3,375,000,000 | ($1,524,619,318) | $1,850,826,021 |
| FY2020 | $3,598,400,000 | ($1,238,200,000) | $2,360,200,000 |
| FY2021 | $3,697,300,000 | ($1,302,000,000) | $2,395,300,000 |
| FY2022 | $3,936,100,000 | ($1,053,200,000) | $2,882,900,000 |
| FY2023 | $4,096,400,000 | ($1,231,800,000) | $2,864,600,000 |
| FY2024 | $4,259,900,000 | ($874,600,000) | $3,385,300,000 |
Figures in current year U.S. dollars. GAO estimates are for calendar years 2016–2019. OCS estimates are for fiscal years 2020–2024.
To correct omissions in the GAO and OCS reports, this report next adds additional forms of spending when reliable data is available.
Spending by Other Pentagon Agencies
The first major omission that this report corrects for involves significant expenditures overlooked by the GAO’s “Burden Sharing” report for the years 2016–2019. The report only uses data provided by the Army, Navy, Air Force, and Marines when in fact the military bureaucracy spends large sums through other Pentagon agencies.[25] The GAO explains that expenditures by the Defense Commissary Agency, Defense Logistics Agency, and other agencies “were outside the scope of this report.”[26] This decision means overlooking around $2.4 billion in spending over the four years and an average of $594.4 million per year.
Data from the government website USASpending.gov shows that Pentagon agencies beyond the Army, Navy, Air Force, and Marines account for 24,937 individual contracts for goods and services with a “place of performance” listed as South Korea in fiscal years 2016–2019. The total value of the contract obligations for those years is $2,377,933,889 ($2.4 billion).[54]
The Defense Logistics Agency (DLA) in particular accounts for $1.8 billion in cumulative spending in 2016–2019. The agency is critical to military operations as the main buyer of fuel, food and beverages, and myriad other supplies and material from copiers to forklifts to containers. The U.S. Transportation Command, which provides transportation services to the military, accounts for another $374.9 million in spending. This again only accounts for contracts listing South Korea as the place of performance and would not include any transportation to or through South Korea involving contracts with a place of performance in the United States or anywhere else in the world.
Table 3 documents spending in other agencies not accounted for by the GAO. The OCS report should include spending by all Pentagon agencies for the years 2020–2024, however, the lack of transparency and other omissions in the report leave considerable ambiguity as to its comprehensiveness.
Table 3: Spending by Pentagon Agencies Other than the Military Branches
| FY2016 | FY2017 | FY2018 | FY2019 | Total | |
| Defense Commissary Agency | $141,214 | $617 | 0 | 0 | $141,830 |
| Defense Contract Management Agency | $4,169,982 | $21,812,950 | $35,012,876 | $36,426,145 | $97,421,954 |
| Defense Information Systems Agency | $3,572,136 | $10,036,345 | $5,073,180 | $2,665,842 | $21,347,502 |
| Defense Logistics Agency | $386,107,679 | $359,669,694 | $625,622,617 | $468,035,737 | $1,839,435,727 |
| Defense Threat Reduction Agency | 0 | 0 | 0 | $25,572,366 | $25,572,366 |
| Department of Defense Education Activity | $3,587,302 | $2,836,806 | $6,743,516 | $4,720,950 | $17,888,576 |
| U.S. Special Operations Command | 0 | 0 | 0 | $1,247,057 | $1,247,057 |
| USTRANSCOM | $78,186,035 | $46,304,583 | $139,734,646 | $110,653,614 | $374,878,877 |
| Grand Total | $475,764,348 | $440,660,994 | $812,186,835 | $649,321,712 | $2,377,933,889 |
Figures in current year U.S. dollars. USASpending.gov, Search by Award & Transactions with place of performance = “Korea, South,” fiscal years 2016–19, awarding agency = Department of Defense, https://www.usaspending.gov/search, accessed July 15, 2026.
Military Personnel Costs Omitted
The next major omission in prior estimates involves the cost of U.S. personnel in South Korea. Military personnel costs reported by the armed forces appear unusually low in both the GAO and OCS data. This may be due to problems with the underlying data used in both reports. In the case of the GAO, for example, the Army and Air Force did not provide actual expenditures data to GAO investigators for personnel costs. Instead, they provided estimated personnel cost data based on reported personnel numbers (known to be unreliable given the military’s desire to disguise the true size of troop deployments) and composite compensation rates (including most but likely not all benefits).[27]
Relying on the armed forces’ data, the GAO reports military personnel costs of, for example, around $70,000 per person in 2019 using the Pentagon’s reported military personnel deployed to South Korea. OCS personnel spending data is generally even lower, showing $64,000 per person in 2016 and less than $70,000 per person in most years. These figures seem unusually low given longstanding, commonly used average estimates for annual U.S. military personnel costs of at least $100,000 per person per year worldwide, with costs abroad almost always exceeding personnel deployed in the United States.[28]
One partial estimate of average personnel costs in 2017 shows an average of $107,106 without accounting for all personnel costs to the federal government.[29] A 2015 Congressional Budget Office estimate revealed costs for military personnel and civilians working for the military in support positions at $136,000 and $96,000 respectively.[30] Note that these are worldwide averages. Costs in South Korea are significantly higher than at bases in the United States: $24,700 to $25,380 more per person annually, according to the best available estimate.[31]
The Congressional Budget Office’s “Atlas of Military Compensation, 2024” appears to provide a more accurate worldwide average. This report uses this data as the basis for its re-calculation of personnel costs in South Korea.
The report first adjusts the Congressional Budget Office (CBO) figures, which are in 2025 constant dollars, for inflation (Table 4). This calculation shows average total annual compensation of $131,015 for military personnel and $102,286 for civilian military personnel in 2016. The figures rise to $179,890 and $136,923 in 2024.[32]
Table 4: Average Military Personnel Costs Worldwide (Congressional Budget Office)[33]
| FISCAL YEAR | CBO AVERAGE MILITARY COMPENSATION PER PERSON WORLDWIDE (2025 $) | CBO AVERAGE CIVILIAN COMPENSATION PER PERSON WORLDWIDE (2025 $) | INFLATION ADJUSTED MILITARY COMPENSATION PER PERSON (current year $) | INFLATION ADJUSTED CIVILIAN COMPENSATION PER PERSON (current year $) |
| 2016 | $175,947 | $137,365 | $131,015 | $102,286 |
| 2017 | $174,068 | $136,932 | $132,702 | $104,391 |
| 2018 | $173,600 | $137,597 | $135,468 | $107,373 |
| 2019 | $172,872 | $137,018 | $137,413 | $108,913 |
| 2020 | $176,033 | $137,773 | $142,079 | $111,199 |
| 2021 | $176,660 | $143,844 | $146,321 | $119,140 |
| 2022 | $174,773 | $139,329 | $157,124 | $125,259 |
| 2023 | $179,085 | $142,184 | $169,026 | $134,198 |
| 2024 | $184,191 | $140,196 | $179,890 | $136,923 |
Figures adjusted for inflation with the U.S. Bureau of Labor Statistics CPI Inflation Calculator.
The report then uses these inflation-adjusted figures to calculate total personnel costs given the number of military personnel and civilian military personnel in South Korea for each year (Table 5).
Table 5: Total Military Personnel Costs in South Korea
| FISCAL YEAR | U.S. MILITARY PERSONNEL IN ROK[34] | U.S. CIVILIAN PERSONNEL IN ROK | TOTAL MILITARY PERSONNEL COMPENSATION | TOTAL CIVILIAN PERSONNEL COMPENSATION | TOTAL PERSONNEL COMPENSATION |
| 2016 | 25,133 | 3,193 | $3,292,799,995 | $326,599,613 | $3,619,399,608 |
| 2017 | 23,411 | 3,136 | $3,106,686,522 | $327,370,396 | $3,434,056,918 |
| 2018 | 25,231 | 2,956 | $3,417,996,640 | $317,395,534 | $3,735,392,174 |
| 2019 | 25,945 | 3,103 | $3,565,169,648 | $337,956,853 | $3,903,126,500 |
| 2020 | 26,257 | 3,042 | $3,730,571,191 | $338,266,871 | $4,068,838,063 |
| 2021 | 24,946 | 3,029 | $3,650,112,939 | $360,876,150 | $4,010,989,090 |
| 2022 | 25,798 | 2,906 | $4,053,472,053 | $364,002,131 | $4,417,474,184 |
| 2023 | 24,437 | 3,061 | $4,130,484,941 | $410,778,762 | $4,541,263,703 |
| 2024 | 24,515 | 3,055 | $4,410,011,195 | $418,298,421 | $4,828,309,616 |
Figures in current year U.S. dollars.
Finally, the report subtracts the prior GAO and OCS personnel cost estimates from the more reliable CBO-based personnel cost estimates to yield net additional personnel ranging from $1.74 billion in 2016 to $2.19 billion in 2024 (Table 6).
Table 6: Additional U.S. Military Personnel Costs in South Korea
| YEAR | PERSONNEL COSTS CALCULATED IN TABLE 5 | GAO/OCS PERSONNEL ESTIMATES[35] | ADDITIONAL PERSONNEL COSTS OMITTED BY GAO/OCS |
| 2016 | $3,619,399,608 | $1,876,687,800 | $1,742,711,808 |
| 2017 | $3,434,056,918 | $2,007,226,750 | $1,426,830,168 |
| 2018 | $3,735,392,174 | $1,983,607,750 | $1,751,784,424 |
| 2019 | $3,903,126,500 | $2,043,182,500 | $1,859,944,000 |
| FY2020 | $4,068,838,063 | $2,038,100,000 | $2,030,738,063 |
| FY2021 | $4,010,989,090 | $2,259,200,000 | $1,751,789,090 |
| FY2022 | $4,417,474,184 | $2,422,300,000 | $1,995,174,184 |
| FY2023 | $4,541,263,703 | $2,606,000,000 | $1,935,263,703 |
| FY2024 | $4,828,309,616 | $2,634,100,000 | $2,194,209,616 |
Figures in current year U.S. dollars. GAO estimates are for calendar years 2016–2019. OCS estimates are for fiscal years 2020–2024. Additional personnel costs are calculated by subtracting GAO and OCS personnel spending data from the CBO’s average per person figures.
Military Construction Costs Omitted
The last major omission that this report corrects for involves military construction costs. The GAO “Burden Sharing” report overlooks $105 million of these expenses. It does so because the report uses the military branches’ data about spending obligations, while overlooking additional military construction funds appropriated by Congress but not yet obligated by the military.[36] In other words, the GAO generally underestimates construction spending because it focuses on contracts entered into during the years under consideration, thus ignoring funding provided by Congress (and, thus, taxpayers) for those years but not yet contracted. Given this common contracting lag, most budget analyses use congressional spending appropriations data rather than obligations data.[37]
For the years in which this report uses OCS figures (FY2020–2024), the OCS appears to accurately document military and family housing construction. This report uses this data with relative but incomplete confidence given that the Pentagon at times hides construction costs in classified budget lines, spending at “worldwide unspecified” locations, and in projects intended for other purposes such as war training exercises.[38]
Table 7: Military Construction Costs in South Korea Omitted from Prior Estimates
| FISCAL YEAR | MILITARY CONSTRUCTION COSTS OMITTED[39] |
| 2016 | 13,749,000 |
| 2017 | 10,405,000 |
| 2018 | 110,118,000 |
| 2019 | -29,484,661 |
| 2020 | $0 |
| 2021 | $0 |
| 2022 | $0 |
| 2023 | $0 |
| 2024 | $0 |
Figures in current year U.S. dollars. GAO estimates are for calendar years 2016–2019. OCS estimates are for fiscal years 2020–2024. Data for 2019 appears as a negative number because spending obligations in that year were larger than congressional appropriations.
Additional Costs Excluded from this Report’s Calculations
Beyond the calculations above, there are additional costs that clearly appear to be excluded from the GAO and OCS estimates as well as several costs that may be excluded. Because of these excluded and potentially excluded costs, as well as other problems with the GAO and OCS data, the true cost of U.S. bases and troops in South Korea may be even higher than this report’s final estimate.
Even if the GAO and OCS data could be treated as reliable, relying on their data alone overlooks military spending in South Korea from other parts of the Pentagon bureaucracy. The following outlines these types of spending. This report excludes them from its calculations because the costs involved cannot be reasonably or reliably estimated. Each category could include spending running into the tens if not hundreds of millions of dollars, which would be costs over and above the total calculation provided above. These costs include:
- Bases, personnel, and activities in South Korea involving classified parts of the Pentagon bureaucracy: Forms of classified spending and spending by classified agencies generally would not appear in the expenditures documented above.
- Military construction costs paid for by accounts linked to “unspecified” locations rather than South Korea: For secrecy and other reasons, the Pentagon disguises the location of some military construction projects by paying for them out of congressionally funded accounts for what are called “worldwide unspecified” locations. Any construction paid for out of these accounts and that actually took place in South Korea would not appear in the calculations above and would add to the totals.
- U.S. forces deploying to South Korea on a temporary or “rotational” basis, including those deployed to participate in war training exercises: The GAO explains that it excludes “costs related to rotational forces that rotate into…South Korea,” including “transportation, training, and sustainment costs for equipment maintained.”[40] Similarly, the OCS only provides spending data for personnel “assigned to permanent duty” and activities “performed on a permanent basis” overseas. Regulations determining reporting requirements for the OCS state that “personnel on temporary duty outside the United States are not included in the overseas amounts.”[41]
- U.S. naval forces on board naval vessels deploying temporarily to South Korea: The GAO and OCS again exclude the costs of temporary or rotational forces, including those aboard ships visiting South Korea but permanently stationed elsewhere. OCS regulations explain, “Because personnel assigned to the deployed fleet are excluded from overseas troop strengths, amounts for deployed steaming days are not included.”[42]
- Indo-Pacific Command (INDOPACOM) costs at the command’s Hawai`i headquarters and other locations outside South Korea related to maintaining bases and troops in the country: These costs are excluded from GAO and OCS data. The OCS explain again explains, “Funding for DoD activities which take place in the United States or in a U.S. territory in support of overseas operations are excluded.”
- Maintenance, training, and other costs of U.S. military personnel, bases, and activities located in other parts of the United States that support the presence of U.S. forces in South Korea: Like spending associated with Indo-Pacific Command operations in Hawai`i and beyond, these costs are excluded. The OCS states, “Overseas amounts exclude the funding of depot maintenance performed in the United States on components/aircraft used by an overseas unit. Similarly, training [for forces stationed abroad] that is conducted in the United States or in U.S. territories is excluded.”[43]
- Activities and operations in South Korea funded by war (“overseas contingency operation”) budgets: Any such costs are excluded from, at very least, the FY2020–2024 calculations relying on OCS data. The OCS report says, “overseas amounts do not include incremental costs associated with contingency operations.”[44]
- Joint Chiefs of Staff war training exercises in South Korea: The GAO and OCS both appear to omit spending on “joint” (cross-armed-forces) war training exercises found within at least the budget of the Joint Chiefs of Staff.[45] Determining precise Joint Chiefs spending in South Korea from what is now called the Joint Training Exercises Evaluation Program budget would be very challenging. A single cancelled exercise in 2018 would have cost $14 million according to Pentagon officials.[46] The true cost of Joint Chiefs of Staff spending in South Korea could be easily two to three or more times these sums.
Costs that May Not Be Included in this Report’s Calculations
In addition to the costs outlined above, the following types of costs may not be part of the underlying GAO and OCS data used in this report’s calculations. Because there is uncertainty about whether they are included in GAO and OCS data, this report excludes these costs to avoid the risk of double counting costs.
Where possible, the report provides indications of the scale of these costs. Each category potentially could add tens if not hundreds of millions of dollars to the total cost of the U.S. military presence in South Korea.
Other war training exercises: These are notoriously difficult to determine given the Pentagon’s refusal to provide cost information and the fact that the military pays for them from numerous budgets. In 2018, when the Pentagon cited the cost of its canceled exercise in South Korea at $14 million, Reuters reported that officials “did not provide details on the cost breakdown or the specifics of what was included. The Pentagon has not divulged the total cost of the multiple drills staged each year by the U.S. and South Korean armed forces. Calculating the cost of military exercises is a complicated process, often requiring data from different branches of the military and spread over several budgets over different years.”[47]
U.S. Forces Korea budgets: In addition to funding provided by the Joint Chiefs of Staff, outlined above, the military typically funds war exercises in part through the military’s combatant commands. In South Korea, the annual budget line item for U.S. Forces Korea (part of the Indo-Pacific Command) likely helps pay for war exercises. The following table shows the total budget of U.S. Forces Korea. This report has been unable to determine what proportion of this budget paid for war exercises or the extent to which all of these costs are reflected in GAO and OCS data. The budget for U.S. Forces Korea, alone, totals more than half a billion dollars over the nine years covered by this report.
Table 8: The Annual Cost of U.S. Forces Korea
| U.S. FORCES KOREA BUDGET[48] | |
| FY2016 | $42,680,000 |
| FY2017 | $45,560,000 |
| FY2018 | $63,268,000 |
| FY2019 | $65,152,000 |
| FY2020 | $57,978,000 |
| FY2021 | $64,021,000 |
| FY2022 | $67,104,000 |
| FY2023 | $67,600,000 |
| FY2024 | $88,463,000 |
Figures in current year U.S. dollars.
The costs of prepositioning weapons and equipment in South Korea, such as in the Army Prepositioned Stocks program.
Special Operations Command, Cyberspace activities, and other specialized forces and programs operating in South Korea that have their own budget line items.
Cooperative Threat Reduction Program funding to reduce nuclear, radiological, chemical, and biological threats worldwide: To reduce such threats, U.S. forces provide “small-scale equipping and training and exercises for designated ROK military and civilian units.” Total spending for the program reached around $350 million in FY2024.[49]
Conclusion
This report shows that the costs of maintaining dozens of U.S. bases and tens of thousands of troops in South Korea are considerably greater than previously estimated. These costs are presented without rounding in the following table. Given the kinds of spending that this report cannot capture and the poor condition of Pentagon accounting practices, actual costs could easily exceed the $5.58 billion spent in FY2024 ($5.91 billion adjusted for inflation).[50]
Table 9: Costs of U.S. Military Bases and Troops in South Korea (ROK)
| YEAR | U.S. COSTS AS PER GAO/OCS ESTIMATES | TOTAL ROK CONTRIBUTIONS | ADDITIONAL U.S. COSTS IDENTIFIED | REVISED U.S. COST ESTIMATES |
| 2016 | $3,121,544,751 | ($1,202,226,615) | $2,232,225,156 | $4,151,543,292 |
| 2017 | $3,342,156,097 | ($1,738,312,122) | $1,877,896,162 | $3,481,740,137 |
| 2018 | $3,530,366,738 | ($1,304,149,724) | $2,674,089,259 | $4,900,306,273 |
| 2019 | $3,375,445,339 | ($1,524,619,318) | $2,479,781,051 | $4,330,607,072 |
| FY2020 | $3,598,400,000 | ($1,238,200,000) | $2,030,738,063 | $4,390,938,063 |
| FY2021 | $3,697,300,000 | ($1,302,000,000) | $1,751,789,090 | $4,147,089,090 |
| FY2022 | $3,936,100,000 | ($1,053,200,000) | $1,995,174,184 | $4,878,074,184 |
| FY2023 | $4,096,400,000 | ($1,231,800,000) | $1,935,263,703 | $4,799,863,703 |
| FY2024 | $4,259,900,000 | ($874,600,000) | $2,194,209,616 | $5,579,509,616 |
Figures in current year U.S. dollars. Numbers may not sum due to rounding. GAO estimates are for calendar years 2016–2019. OCS estimates are for fiscal years 2020–2024.
That there is not a clear accounting of what U.S. taxpayers are paying to maintain a military presence in South Korea underlines many of the deficiencies of Pentagon accounting systems and the urgency of ensuring the Pentagon can track its spending and assets given that it accounts for around half of yearly discretionary spending.
The case of South Korea is not unique. The costs of maintaining around 800 or more bases and hundreds of thousands of troops outside the United States have been poorly understood and reported for decades. As discussed above, the place where Congress requires the Pentagon to track costs abroad, the Overseas Cost Summary, provides data of limited accuracy and reliability. The Pentagon should significantly improve the accuracy of the OCS. Taxpayers, politicians, and analysts should be able to understand the true costs of maintaining bases and troops abroad. Total costs are now likely $100 billion or more.[51] Congress should fulfill its oversight role to ensure the Pentagon provides an accurate OCS.
Given the opportunity costs of billions of dollars in U.S. taxpayer investment—how these billions are not being invested—continued spending on the U.S. military presence in South Korea should be analyzed and debated. The U.S. presence in South Korea should also be analyzed and debated on national security grounds. For too long, too many have continued to assume, with little or no evidence, that U.S. bases and troops are improving U.S., South Korea, and regional security.
David Vine is a political anthropologist and author of a trilogy of books about war and peace including Base Nation: How U.S. Military Bases Abroad Harm America and the World and Island of Shame: The Secret History of the U.S. Military Base on Diego Garcia. Vine was a professor of anthropology at American University in Washington, DC for 18 years before resigning with the rank of full professor in 2024. For more information see https://www.davidvine.net and https://www.basenation.us. Contact [email protected].
Appendix: Republic of Korea (ROK) Costs to Support the U.S. Military Presence, 2020–24
| ROK BURDENSHARING PAYMENTS[52] | IN-KIND MILITARY CONSTRUCTION COSTS[53] | TOTAL ROK CONTRIBUTIONS | |
| FY2020 | $696,000,000 | $542,200,000 | $1,238,200,000 |
| FY2021 | $886,000,000 | $416,000,000 | $1,302,000,000 |
| FY2022 | $696,000,000 | $357,200,000 | $1,053,200,000 |
| FY2023 | $482,000,000 | $749,800,000 | $1,231,800,000 |
| FY2024 | $494,000,000 | $380,600,000 | $874,600,000 |
[1] Department of War [Defense], “Base Structure Report FY2025,” n.d.[2025], available at https://www.basenation.us/bsr.html [these reports were previously available at the following address but appear to have been removed: https://www.acq.osd.mil/eie/imr/rpid/library.html]; Defense Manpower Data Center, “Number of Military and DoD Appropriated Fund (APF) Civilian Personnel,” June 2025, https://dwp.dmdc.osd.mil/dwp/app/dod-data-reports/workforce-reports.
[2] Senate Armed Services Committee, “Senate Armed Services Committee Hearing on Gen. Brooks Nomination,” CQ Transcripts, April 26, 2016, https://www.army.mil/article/166787/senate_armed_services_committee_hearing_on_gen_brooks_nomination.
[3] Updating 2013 figures of $10,000-$40,000; $16,600; and $17,500 in Michael Lostumbo, et al., “Overseas Basing of U.S. Military Forces: An Assessment of Relative Costs and Strategic Benefits,” RAND Corporation, 2013, p. 175, 212–213. Figures updated using the U.S. Bureau of Labor Statistics, CPI Inflation Calculator, https://www.bls.gov/data/inflation_calculator.htm, accessed July 15, 2026.
[4] See David Vine, Base Nation: How U.S. Military Bases Abroad Harm America and the World (New York: Metropolitan Books/Henry Holt, 2015), 195–213.
[5] Lindsay Koshgarian, “Take 7: The Pentagon Fails Another Audit,” November 25, 2024, https://www.nationalpriorities.org/blog/2024/11/25/take-7-pentagon-fails-another-audit/.
[6] Estimates for 2016–2019 are from Government Accountability Office [GAO], “Burden Sharing: Benefits and Costs Associated with the U.S. Military Presence in Japan and South Korea,” Washington, DC, March 2021. Estimates for fiscal years 2020–2024 are from the “Overseas Cost Summary” reports found in Pentagon budget documents for fiscal years 2022, 2023, 2024, 2025, Office of the Under Secretary of Defense (Comptroller)/Chief Financial Officer, “Operations and Maintenance Overview,” United States Department of Defense, available at https://comptroller.war.gov/Budget-Materials/.
[7] For 2016–2019, see GAO, “Burden Sharing,” 49–53. For 2020–2024, see Appendix.
[8] Nicole Gaouette, “Trump Hikes Price Tag for US Forces in Korea Almost 400% as Seoul Questions Alliance,” CNN.com, November 15, 2019, https://www.cnn.com/2019/11/14/politics/trump-south-korea-troops-price-hike/index.html.
[9] U.S. Department of Defense, “Operations and Maintenance Overview, Fiscal Year 2019 Budget Estimates,” Office of the Secretary of Defense (Comptroller), March 2018, 201, 203, https://comptroller.war.gov/Portals/45/Documents/defbudget/fy2019/fy2019_c1.pdf.
[10] The South Korean government reports the government makes additional in-kind contributions that are not formally valued, such as providing land for bases free of charge. Most countries hosting U.S. bases abroad provide in-kind contributions, which are generally hard to value.
[11] GAO, “Burden Sharing,” 43–44, 50.
[12] E.g., the Pentagon’s Overseas Cost Summary shows U.S. costs of $4.3 billion in FY2018 while the GAO reports costs of $3.5 billion for the 2018 calendar year. It is unlikely that the difference between the fiscal and calendar year calculations can explain the divergence. In some years the Summary’s calculation is lower than the GAO’s.
[13] National Priorities Project, Trade-Offs Calculator, accessed October 31, 2025, https://www.nationalpriorities.org/interactive-data/trade-offs.
[14] Lindsay Koshgarian, “Take 7: The Pentagon Fails Another Audit,” November 25, 2024, https://www.nationalpriorities.org/blog/2024/11/25/take-7-pentagon-fails-another-audit/; Taxpayers for Common Sense, “Pentagon Fails Audit for 7th Straight Year,” November 18, 2024, https://www.taxpayer.net/national-security/pentagon-fails-audit-for-7th-straight-year/.
[15] Dave Gilson, “Don’t Tread on Me,” Mother Jones, January/February 2014, 31; Koshgarian, “Take 7.”
[16] The difference between fiscal year and calendar year spending is typically not large but adds imprecision to the calculation in places where the report must combine the two types of data.
[17] “The services were able to provide the data by calendar year or by quarter, for each appropriation account, with three exceptions. The Air Force was able to provide military personnel obligations by fiscal year only, and the Marine Corps was able to provide operation and maintenance and family housing operation and maintenance obligations by fiscal year only.” GAO, “Burden Sharing,” p. 37.
[18] E.g., U.S. Department of Defense, “Defense Operation and Maintenance Overview Book, Fiscal Year 2024 Budget Estimates,” Washington, DC, May 2023, 191–194. The requirement appears in Section 8125 of the fiscal year 1989 Department of Defense Appropriations Act (P.L. 100-463). See also 10 U.S.C. 113.
[19] Reuters, “U.S. Military Completes Withdrawal from Key Drone Base in Niger,” august 5, 2024, https://www.reuters.com/world/africa/us-military-completes-withdrawal-key-drone-base-niger-2024-08-05/.
[20] Department of Defense, “Overseas Cost Report,” Financial Management Regulation vol. 2B, chap. 15, DoD 7000.14-R, August 2022, 5.
[21] Vine, Base Nation, 54.
[22] For more details see Vine, Base Nation, 197–213.
[23] Estimates for 2016–2019 are from GAO, “Burden Sharing.” Estimates for fiscal years 2020–2024 are from the “Overseas Cost Summary” reports found in Pentagon budget documents for fiscal years 2022, 2023, 2024, 2025, Office of the Under Secretary of Defense (Comptroller)/Chief Financial Officer, “Operations and Maintenance Overview,” United States Department of Defense, available at https://comptroller.war.gov/Budget-Materials/.
[24] For 2016–2019, see GAO, “Burden Sharing,” 49–53. For 2020–2024, see Appendix.
[25] The Space Force was created in late 2019, which is fiscal year 2020.
[26] GAO, “Burden Sharing,” 42n1.
[27] “According to Air Force officials, the Air Force uses a composite rate to track military personnel obligations in Japan and South Korea. To determine the composite rate, the Air Force applies manpower reports from Air Force Manpower, Personnel, and Services that identify the number of servicemembers stationed in each country in which the Air Force has a presence, as well as the rank and service time for each servicemember. Then, the Air Force applies base pay, retirement pay accrual, overseas housing allowance, and certain incentive pay data to the manpower data to determine military personnel obligations.” GAO, “Burden Sharing,” 45 (see also p. 44 for the Army’s methodology).
[28] Lostumbo, et al., “Overseas Basing of U.S. Military Forces,” 113.
[29] Kathleen Blakely, “Military Personnel,” Center for Strategic and Budgetary Analysis, August 15, 2017, https://csbaonline.org/reports/military-personnel.
[30] Congressional Budget Office, “Replacing Military Personnel in Support Positions with Civilian Employees,” December 2015, https://www.cbo.gov/sites/default/files/114th-congress-2015-2016/reports/51012-Military_Civilian_Mix_OneCol.pdf.
[31] Updating figures of $16,600-$17,500 in Lostumbo, et al., “Overseas Basing of U.S. Military Forces,” 212–213. Figures updated using the U.S. Bureau of Labor Statistics CPI Inflation Calculator, https://www.bls.gov/data/inflation_calculator.htm, accessed July 15, 2026.
[32] Congressional Budget Office, “Atlas of Military Compensation, 2024,” January 2025, figure 3, www.cbo.gov/publication/60886. Inflation adjustments made with the U.S. Bureau of Labor Statistics CPI Inflation Calculator, accessed October 31, 2025.
[33] Congressional Budget Office, “Atlas of Military Compensation, 2024,” figure 3.
[34] Personnel figures come from quarterly Pentagon reports in the middle of each fiscal year, March 31. Figures for 2023 are from September 30 because March figures are incomplete due to a lack of Army data. See Defense Manpower Data Center (DMDC), “Number of Military and DoD Appropriated Fund (APF) Civilian Personnel.” See https://dwp.dmdc.osd.mil/dwp/app/dod-data-reports/workforce-reports.
[35] Estimates for 2016–2019 are from GAO, “Burden Sharing.” Estimates for fiscal years 2020–2024 are from the “Overseas Cost Summary” reports found in Pentagon budget documents for fiscal years 2022, 2023, 2024, 2025, Office of the Under Secretary of Defense (Comptroller)/Chief Financial Officer, “Operations and Maintenance.”
[36] GAO, “Burden Sharing,” p. 43.
[37] The GAO likely focused on obligations here because it focused on obligations in calculating military personnel costs. While this makes sense for personnel costs given that there are no specific line items for personnel in South Korea, the availability of clear line items for military construction and family housing construction in South Korea makes appropriations the more accurate metric here. Note that in one year, 2019, obligations exceeded appropriations, which created an overestimate of spending for that year. In total, however, the GAO underestimates by $105 million.
[38] Vine, Base Nation, 202–03.
[39] See Office of the Under Secretary of Defense (Comptroller), “Construction Programs (C-1), Department of Defense Budget,” for fiscal years 2018–2021, available at https://comptroller.war.gov/Budget-Materials/. Figures come from the budget documents for the fiscal year two years after the year cited, which provides actual spending authority, appropriations, and total obligational authority. The figures in the table represent total obligational authority.
[40] GAO, “Burden Sharing,” 6n6.
[41] Department of Defense, “Overseas Cost Report,” in “Financial Management Regulation,” Volume 2B, Chapter 15, (DoD 7000.14-R), August 2022, 5.
[42] Department of Defense, “Overseas Cost Report,” in “Financial Management Regulation,” 5.
[43] Department of Defense, “Defense Operation and Maintenance Overview Book, Fiscal Year 2025 Budget Estimates,” Washington, DC, March 2024, 188.
[44] Department of Defense, “Defense Operation and Maintenance Overview Book, Fiscal Year 2025,” 188.
[45] The GAO confirmed in an email that its only data came from the four armed forces and not from the Joint Chiefs of Staff. OCS instructions do not require the Joint Chiefs to report spending data overseas. Reporting is only required by Congressional mandate to “Service components and Defense Agencies and Field Activities.” Department of Defense, “Overseas Cost Report,” 4.
[46] Pentagon officials may have had reason to underestimate the war exercise’s true cost given the opposition of many in the military to President Trump’s cancelation, citing cost savings as part of his motivation. Idrees Ali, “Cost of One of those ‘Expensive’ U.S.-South Korea Military Exercises? $14 Million,” Reuters,July 6, 2018, https://www.reuters.com/article/us-northkorea-usa-military-cost/cost-of-one-of-those-expensive-u-s-south-korea-military-exercises-14-million-idUSKBN1JW348.
[47] Ali, “Cost of One of those ‘Expensive’ U.S.-South Korea Military Exercises?”.
[48] Figures come from the Operation and Maintenance budget documents for the fiscal year coming two years after the year cited, which provides actual spending obligations. Because there was no line item for U.S. Forces Korea in FY2016–2017, the report used FY2020 as a guide. In that fiscal year, the U.S. Forces Korea budget represented 20% of the total Indo-Pacific Command budget. The report applied this percentage to the FY2016–2017 Pacific Command budget, which was $213,400,000 in FY2016 and $227,800,000 in 2017 according to the FY2018 and FY2019 Operation and Maintenance budget document submissions.
[49] Department of Defense, “Defense Operation and Maintenance Overview Book, Fiscal Year 2025,” 23–29.
[50] Figures updated using the U.S. Bureau of Labor Statistics CPI Inflation Calculator, https://www.bls.gov/data/inflation_calculator.htm, accessed July 15, 2026.
[51] Updating the FY2021 estimate in David Vine, Patterson Deppen, and Leah Bolger, “Drawdown: Improving U.S. and Global Security Through Military Base Closures Abroad,” Quincy Brief no. 16, Quincy Institute for Responsible Statecraft and World BEYOND War, September 20,
https://quincyinst.org/report/drawdown-improving-u-s-and-global-security-through-military-base-closures-abroad/. Figures updated using the U.S. Bureau of Labor Statistics CPI Inflation Calculator, https://www.bls.gov/data/inflation_calculator.htm, accessed July 21, 2026..
[52] See Office of the Under Secretary of Defense (Comptroller), “National Defense Budget Estimates” [“Green Book”] for fiscal years 2022–2025, available at https://comptroller.war.gov/Budget-Materials/.
[53] See “Host Country In-Kind Contributions Republic of Korea Funded Construction” in Office of the Under Secretary of Defense (Comptroller), “Construction Programs (C-1), Department of Defense Budget,” for fiscal years 2020–2024, available at https://comptroller.war.gov/Budget-Materials/.
[54] Figures in current year U.S. dollars. USASpending.gov, Search by Award & Transactions with place of performance = “Korea, South,” fiscal years 2016–19, awarding agency = Department of Defense, https://www.usaspending.gov/search, accessed July 15, 2026
