The XI Corps was a unit of the United States Army that played a significant role during the American Civil War. Established in 1862, it was primarily composed of volunteer soldiers and was involved in several key battles, including the Battle of Gettysburg. The corps was known for its diverse composition, which included troops from various states and backgrounds. After the Civil War, the XI Corps continued to exist and was reactivated during the Spanish-American War and World War I. It was eventually inactivated in 1922. The corps is remembered for its contributions to military history and its evolution through different conflicts.