A major supply depot was situated at the fort . Confederate general Sterling Price hoped to capture the town , but the closest the Confederate force came to the garrison was 10 miles ( 16 km ) away at Battle of Dry Wood Creek . The site was strategically important as it was within a Southern @-@ sympathizing area and close to the Confederate state of Arkansas and the " unstable " Indian Territory ( present @-@ day state of Oklahoma ) , where many of the members of the Five Civilized Tribes were allied with the Confederates . The fort served as a " general hospital " ( large military hospital ) and prison until after the war . Following the end of the war , in October 1865 the US Army left the facilities and sold off by auction what they controlled .