As the first Union attempt at Vicksburg was gaining momentum in the fall of 1862 the Confederate leaders on the other side of the river also worried about possible action there. In Arkansas MG Theophilus Holmes, commander of the Trans- Mississippi Department, ordered Colonel John Dunnington to locate a suitable position for a fortification on the Arkansas River. With the assistance of two officers from the Confederate Corps of Engineers, Dunnington selected a site near the small town of Arkansas Post. A company of sappers and miners (Clarkson’s) was assigned to the work along with the 19th Arkansas Infantry and LTC William Crawford’s Arkansas Infantry Battalion. Dunnington was also authorized to make levies against the local slave population for laborers. Before construction got under way Holmes also ordered Colonel Robert Garland’s brigade of Texans (24th and 25th Texas Cavalry [dismounted] 6th Texas Infantry), Hart’s Arkansas Battery, and Denson’s company of Louisiana cavalry to supply fatigue details and then garrison the fort. Working feverishly the men attempted to complete the fort before the seasonal rise in the river would allow Union gunboats access to the river.
By November construction was nearly complete. Post of Arkansas, as it was called, was a 100 yard square fort with bastions at each corner. Each bastion contained three gun platforms. A ditch, 20 feet deep and 8 feet wide, surrounded the fort, which was covered by infantry who would use a banquette on the interior slope of the parapet to fire into or over the ditch. But the primary purpose of the fort was to stop river traffic thus the heaviest armament was positioned in the bastion overlooking a sharp turn in the river. This bastion was a casemate , 18 feet X 15 feet, reinforced with 42 inches of oak timbers. The roof had an equal covering of oak supplemented by iron plate. To arm the fort with heavy guns the C.S.S. Ponchartrain was stripped of its armament, supplying two 9-inch and one 8-inch Columbiads . These long range pieces were perfect for river defense and 35 members of the Ponchartrain’s crew remained behind to man them as the vessel steamed upriver to Little Rock. The remaining gun positions were filled with four 10 pound Parrott rifles and four 6 pound smoothbores. The inside of the fort contained three buildings, two magazines, and a well-protected water supply in the form of a well. Outside the fort secondary defenses included a line of trenches that ran westward to anchor on Post Bayou. All told the tidy little fort presented a serious obstacle to any vessel wishing to go upriver without their permission. It was sure to gain the attention of the enemy.Arkansas Post (Campaign Series)