Arkansas in the American Civil War readmitted in July 1866. Arkansas in the American Civil War During the American Civil War, Arkansas was a Confederate state, though it had initially voted to remain in the Union. Following the capture of Fort Sumter in April 1861, Abraham Lincoln called for troops from every Union state to put down the rebellion, and Arkansas and several other states seceded. For the rest of the war, Arkansas played a major role in controlling the vital Mississippi River and neighboring states, including Tennessee and Missouri. It raised 48 infantry regiments, 20 artillery batteries, and over 20 cavalry regiments for the Confederacy,
Trans-Mississippi Theater of the American Civil War representatives on June 23, 1865. Trans-Mississippi Theater of the American Civil War The Trans-Mississippi Theater of the American Civil War consists of the major military operations west of the Mississippi River. The area is often thought of as excluding the states and territories bordering the Pacific Ocean, which formed the Pacific Coast Theater of the American Civil War (1861-1865). The campaign classification established by the National Park Service of the U.S. Department of the Interior is more fine-grained than the one used in this article. Some minor NPS campaigns have been omitted and some have been combined into larger categories.