1st Arkansas Infantry Battalion (Union)  The 1st Battalion Arkansas Volunteer Infantry (1862) was an infantry battalion that served in the Union Army during the American Civil War. Although Arkansas joined the Confederate States of America in 1861, not all of its citizens supported secession. The 1st Battalion Arkansas Volunteer Infantry was organized at Helena, Arkansas, July 20, 1862. Mustered out December 31, 1862. Attached to District of Eastern Arkansas and duty at Helena, Ark., till October. Moved to St. Louis, Mo., and duty at Benton Barracks, Mo., till December. The battalion was mustered out on December 31, 1862.