Marks' Mills is one of three Civil War sites in south-central Arkansas from the Union Army's 1864 Red River Campaign, along with Poison Springs and Jenkins Ferry. On April 20, 1864, a 150-wagon Union supply train from Pine Bluff was attacked here, and the loss led General Steele to abandon his march toward Shreveport and plan a retreat from Camden to Little Rock. The park has interpretive exhibits and picnic sites and is open all year. The phone is the Arkansas State Parks main line.