The Army of the Cumberland was a major Union army during the American Civil War, primarily active in the Western Theater. Established in 1862, it played a crucial role in several key battles, including the Battle of Stones River and the Battle of Chattanooga. Commanded by notable leaders such as Major General William S. Rosecrans and Major General George H. Thomas, the army was instrumental in securing Union victories in Tennessee and Georgia. Its efforts helped to weaken the Confederate Army and contributed to the overall success of the Union war strategy.