After the Dec. 7, 1862, Battle of Prairie Grove, the Union Frontier Division set out to strike Confederate forces on the Arkansas River. On Dec. 27, 8,000 Union troops headed south through the Boston Mountains. They hit Van Buren on Dec. 28 and opened fire with their cannon, some of which may have been placed at the Drennen-Scott House. Confederate guns responded from Fort Smith, and the artillery dueled until sunset. The Confederates abandoned Fort Smith that night. The Federals burned boats and supplies and headed north, joined by former slaves.