The XI Corps is a corps-level formation of the United States Army. It was originally established during World War I but was disbanded after the war ended. In 1950, it was reactivated for service in the Korean War and was later deactivated again in 1954. During the Cold War, it was once more reactivated as part of the U.S. Army Training and Doctrine Command (TRADOC). As of 2021, the XI Corps is a component of the United States Army Pacific (USARPAC) and is responsible for providing operational command, control, and coordination to U.S. forces in the Pacific region during a contingency or war. The corps headquarters is located at Joint Base Lewis-McChord in Washington State.