The Second Corps was a major unit of the Union Army during the American Civil War. Established in 1862, it played a crucial role in several key battles, including the Battle of Antietam and the Battle of Gettysburg. The corps was known for its effective leadership and organization, particularly under commanders like Major General John Sedgwick. The Second Corps was composed of multiple divisions, each containing several brigades. It was instrumental in various military campaigns, contributing to the overall success of the Union forces. The corps was eventually disbanded in 1865 after the war concluded, marking the end of its significant contributions to American history.