In February and March 2009, the Obama Administration announced its overall plans to increase troop levels in Afghanistan and decrease troop levels in Iraq for 2009 through 2011. Using several Department of Defense (DOD) data reports, this report describes, analyzes, and estimates deployed troop strength from the 9/11 attacks to FY2012 to provide Congress with a tool to assess current and future DOD war funding requests; implications for the U.S. military presence in the region; and deployment burdens on individual service members and each of the services. In February and March 2009, President Obama approved the deployment of an additional 21,000 service members to Afghanistan in the spring and summer of 2009, meeting most of the request from Secretary of Defense Robert Gates, and General David McKiernan, former Commanding General of the International Security Assistance Force (ISAF) in charge of the Afghan theater of operations. According to the President, these additional troops are intended to "stabilize a deteriorating situation in Afghanistan." In the winter of 2008 before leaving office, President Bush approved deploying an additional Brigade Combat Team (BCT) of about 9,000 to Afghanistan in January 2009. Still pending is a DOD request for an additional 9,000 troops that could be deployed in Afghanistan sometime in the winter of 2009. Last October, General David McKiernan requested about 35,000 more combat troops for Afghanistan composed of four Brigade Combat Teams with support. Later, 4,000 trainers were added, bringing the total request to 39,000. About 30,000 of that request has been approved by either former President Bush or President Obama. With these increases, CRS estimates the number of U.S. troops deployed in Afghanistan is expected to reach about 63,450 by the end of FY2009, double that of the prior year; this estimate is somewhat lower than the Administration's estimate of 68,000. If some 31,000 coalition troops from NATO nations serving in the International Security Assistance Force are included, average monthly foreign troop strength in Afghanistan would be about 81,000 in FY2009, and 93,450 in FY2010. These figures do not include from 10,000 to 17,000 more U.S. troops dedicated to Operation Enduring Freedom (OEF), most of whom provide support in the region. Because all but the 2,000 troops in the Philippines are linked to the Afghan War, CRS uses OEF and the Afghan War interchangeably in this report. In a speech to U.S. Marines at Camp Lejeune on February 27, 2009, President Obama announced that the Administration's review of U.S. strategy in Iraq was complete and that the U.S. mission in Iraq would shift from combat to supporting and training Iraqi security forces, and that U.S. troops would decline from the February 2009 level of about 140,000 in-country to 35,000 to 50,000 troops by August 31, 2010. In addition, the policy would meet the deadlines set in the January 1, 2009 Security Agreement with Iraq that requires all U.S. combat troops to move outside of cities by the end of June 2009, as recently took place, and that all U.S. troops leave Iraq by December 31, 2011. The Administration has not explained the effect of these withdrawals on other troops deployed for OIF, or the Iraq War, which includes not only U.S. troops located in Iraq but also some 80,000 to 90,000 troops providing theater-wide support in neighboring areas. CRS uses OIF and the Iraq War interchangeably in this report. The President reportedly considered options ranging from the 16-month withdrawal proposed during the campaign to a 23-month alternative reportedly favored by some in the military. Ultimately, the President adopted a 19-month plan. DOD spokesmen have suggested that increasing troop levels in Afghanistan depends, at least in part, on decreasing troop levels in Iraq if the services are to continue current 12-month tours. During the surge in troops in 2007 and 2009, tours grew to 15 months, a move that proved very unpopular. These two decisions about troop levels are reflected in the FY2009 Supplemental request sent to Congress in early April and the FY2010 war request submitted in early May 2009 with the regular budget. The FY2009 Supplemental covers DOD's war costs for the rest of this fiscal year that ends September 30, 2009 because DOD received only part of its war funding in the FY2009 bridge fund enacted last summer. According to statute, the Administration is to include a full year of war costs with the regular budget in FY2010, and provide separate budget displays for each war, and troop strength levels as well as the underlying assumptions. DOD provided general information about troop levels but not the underlying assumptions or separate budget displays for each operation in its FY2010 request. The Administration's decisions to reduce the number of troops in Iraq reflects declining levels of violence and peacefully conducted provincial elections that took place in January 31, 2009, while its decision to increase troop levels in Afghanistan reflects rising levels of violence and elections slated for August of 2009. Another important element in decisions about troop levels is the effectiveness of Afghan and Iraqi security forces, where the U.S. has invested $38.9 billion thus far to train and equip these forces. To identify the implications of troop levels for these and other policy issues, this report explains how and why measures of troop levels in five different DOD data sources differ; estimates future troop strength in Afghanistan and Iraq for FY2009-FY2012 under the Obama Administration plan using "Boots on the Ground," the most commonly cited measure; discusses the potential cost implications of these changes in troop levels along with other adjustments; analyzes and explains past trends in troop levels for the Afghan and Iraq Wars under the different measures; and measures contributions and burdens of deployment for the four services. For detailed description and analysis of the political and military context for changes in troop levels in Afghanistan and Iraq, see the following CRS Reports: CRS Report RL30588, Afghanistan: Post-Taliban Governance, Security, and U.S. Policy and CRS Report RL31339, Iraq: Post-Saddam Governance and Security , by [author name scrubbed]; and CRS Report R40156, War in Afghanistan: Strategy, Military Operations, and Issues for Congress and CRS Report RL34387, Operation Iraqi Freedom: Strategies, Approaches, Results, and Issues for Congress , by [author name scrubbed]. When discussing deployed troop levels, it is important to be clear about which troops are included and which troops are not included. CRS analyzed five different sources for DOD troop strength for the Afghan and Iraq Wars ranging from including only those troops deployed in-country to including not only troops deployed in-country but also those providing theater-wide support in the region. In the June preceding the September 11, 2001 attacks, the United States had about 26,000 troops stationed in the U.S. Central Command region, which encompasses Afghanistan and Iraq and neighboring areas. Most troops were located in Kuwait, Saudi Arabia and on ships in the region, including some conducting over flight operations for Northern and Southern Watch to contain Saddam Hussein after the first Gulf War. Based on the most comprehensive measure of troop strength, DOD's Defense Manpower Data Center's Location Report , capturing all troops deployed for both wars, there were 294,000 U.S. troops in the region for Operation Enduring Freedom and Operation Iraqi Freedom in December 2008, more than ten times the level seven years ago (see Figure 1 and Box 1 ). Figure 1 shows the number and location of these U.S. troops in December 2008, with an allocation between OEF or OIF based on where personnel are located that generally reflects guidelines developed by the Joint Staff, Joint Chiefs of Staff and Central Command. These allocations may or may not match distributions of war costs, which are collected separately by each service. This figure of 294,000 troops is over 100,000 higher than the December 2008 total of 181,000 reported in DOD's oft-cited Boots on the Ground," (BOG) report. Military leaders, DOD press spokesmen and Members of Congress use the monthly BOG figures to give a snapshot of the number of troops deployed in-country in Afghanistan and in Iraq. For example, Admiral Mullen, Chair of the Joint Chiefs of Staff, said there were 150,000 troops in Iraq "right now" on November 17, 2008, and Pentagon press secretary, Geoff Morrell said in January 2009 that the proposal to add 30,000 troops in Afghanistan would double the number there. DOD has reported these Boots on the Ground figures to Congress each month since 2008. As of the most recent data for April 1, 2009, DOD reported that there were 178,400 Boots on the Ground in Afghanistan and Iraq, slightly lower than in December 2008 reflecting the withdrawal of some troops from Iraq offset by the deployment of additional troops to Afghanistan. Part of the difference between DOD's Boots-on-the-Ground figures and the Location Report is definitional. Boots on the Ground reports only personnel in Afghanistan or in Iraq while the Location Report counts deployments of all military personnel tracked as part of OEF and OIF, including primarily personnel providing support in neighboring countries, as well as about 2,000 OEF personnel engaged in counter-terror operations in the Philippines. Relying primarily on guidelines developed by staff of the Joint Chiefs of Staff and Central Command, CRS allocated troops to each operation based on their location (see Figure 1 and Box 1 ). CRS uses the Iraq War interchangeably with OIF and the Afghan War interchangeably with OEF to include not only troops in-country, but also those providing theater-wide support primarily in the region. (All but the 2,000 troops in the Philippines are part of OEF or the Afghan War.)