The Department of the Cumberland was a military district established during the American Civil War. It was created in 1862 and primarily covered parts of the state of Tennessee. The department was responsible for overseeing Union operations in the region, which included managing troops and coordinating supply lines. The department was named after the Cumberland River, a significant waterway in the area. It played a crucial role in various battles and campaigns, including the Battle of Nashville. The leadership of the department changed several times, with notable commanders such as Major General George H. Thomas overseeing its operations.