After a divided Arkansas seceded from the Union in 1861, it became a strategic target for both North and South because of its location on the Mississippi River and its role as a gateway to the Southwest. Included among the state's more than 750 military engagements were a number of major conflicts.
The war's largest battle west of the Mississippi was fought at Pea Ridge in March 1862. Participating were some 26,000 soldiers. The Union victory dashed Confederate hopes of occupying Missouri.
In December, 1862, more than 11,000 Confederates battled Union forces at Prairie Grove in a failed attempt to prevent federal occupation of Fort Smith.
The control of Arkansas River commerce was at stake when 30,000 Union troops overwhelmed 5,000 Confederates at Arkansas Post in January 1863, while control of the Mississippi figured in the Battle of Helena on July 4, 1863.
Union forces occupied Little Rock on Sept. 10, 1863, despite numerous skirmishes. The state's Confederate government moved its capital to the town of Washington.
In the spring of 1864, 13,000 federal troops headed southwest from Little Rock in an attempt to complete the Union conquest of the state. That failed venture is now known as the Red River Campaign.