The XII Corps was a unit of the United States Army that played a significant role during the American Civil War. Established in 1862, it participated in key battles, including the Battle of Gettysburg and the Battle of Vicksburg. The corps was known for its effective leadership and strategic maneuvers, contributing to the Union's overall success. After the Civil War, the XII Corps was reactivated during the World War II era. It was involved in various campaigns in the European theater, showcasing its adaptability and resilience. The corps was eventually inactivated after the war, marking the end of its operational history.