Organized at Corinth, Mississippi in June, 1862, with four companies - each one composed of men handpicked for their marksmanship abilities from the 18th, Dockery's 19th, 20th, and Craven's 21st Arkansas Infantry regiments. Commanded by Major William F. Rapley, the battalion served with distinction in Hebert's Brigade at the battle of Corinth on October 3-4, 1862, and at Hatchie Bridge during the retreat from Corinth, and subsequently throughout the Vicksburg campaign in the fall of 1862 through the summer of 1863. The battalion was employed to oppose the federal Steele's Bayou Expedition on March 14-27, 1863 and at Rolling Fork on March 20; and subsequently fought at Grand Gulf (April 29), Port Gibson (May 1), Champion Hill (May 16), Big Black River (May 17), and was besieged with the Vicksburg garrison during the 45-day siege of that strongpoint from May 20 until July 4, 1863. Surrendered with the Vicksburg garrison on July 4, 1863 and was paroled at that place later that month. Survivors of the battalion returned home to Arkansas, where many of them reformed their old unit under Brig. Gen. James F. Fagan's Cavalry Division , fighting in the Camden Expedition and at the battle of Marks' Mill. There is little or no record of the unit's activity after this point.
12th Battalion Sharpshooters was organized during the early spring of 1862 with men from the southeastern section of the state. It moved east of the Mississippi River and fought at Iuka and Corinth where 57 men were disabled. Later the unit was assigned to General M. E. Green's command, Department of Mississippi and East Louisiana, and was captured at Vicksburg on July 4, 1863. After being exchanged it was attached to General Dockery's Brigade, Trans-Mississippi Department, and was active in the engagement at Marks' Mills. It later disbanded. Major William F. Rapley commanded the battalion.