When Arkansas seceded from the Union in 1861, it was a thriving state. But the Civil War and Reconstruction left it reeling, impoverished, and so deeply divided that it never regained the level of prosperity it had previously enjoyed. Although most of the major battles of the war occurred elsewhere, Arkansas was critical to the Confederate war effort in the vast Trans-Mississippi region, and Arkansas soldiers served - some for the Union and more for the Confederacy - in every major theater of the war.