Following the Union capture of Little Rock on Sept. 10, 1863, citizens of Pine Bluff asked for a Union garrison for protection, and Gen. Frederick Steele sent the veteran 5th Kansas Cavalry and 1st Indiana Cavalry to establish a post there. Union commander Col. Powell Clayton made the Boone-Murphy House, then at 702 W. Second Ave., his headquarters and home. With help from former slaves from nearby refugee camps, Clayton's troops repelled Confederate attackers on Oct. 25, 1863, and kept control of Pine Bluff. More broadly, after a January 1863 victory at Arkansas Post, Union strategists sought control of the Arkansas River valley to divide the Trans-Mississippi Confederacy and help return a secessionist capital to the Union. The capture of Little Rock and Fort Smith in September 1863 gave U.S. forces effective dominance of the river valley, and a permanent garrison at Pine Bluff strengthened Union control of the lower Arkansas River and a vital crossroads while also making the town an inviting Confederate target.