The Division of the Missouri was a military unit of the Union Army during the American Civil War. It was established in 1861 and played a crucial role in the western theater of the war. The division was involved in several key battles, including the Battle of Pea Ridge and the Siege of Vicksburg, contributing to the Union's efforts to control the Mississippi River. Under the command of various leaders, including Major General John A. McClernand, the Division of the Missouri aimed to secure strategic locations and support other Union forces. Its operations helped to weaken Confederate control in the region and ultimately contributed to the Union's victory.