Fort Belknap was established in 1851 as a northern anchor on the Texas frontier line of defense. The garrison safeguarded travelers along a network of frontier trails, most notably the Butterfield Overland Mail route. Abandoned by federal troops in 1861, state troops of the Frontier Regiment under Col. James M. Norris occupied the fort at various times throughout the Civil War. Federal troops reoccupied it in 1867 before it was finally abandoned the same year. A handful of buildings remain in the park-like setting, and a museum in the old commissary chronicles frontier history.
Fort Belknap was designated as a National Historic Landmark in 1960.