Blackjack Mountain is a seventeen-mile ridge in southeastern Oklahoma's Ouachita Mountains, rising to 1,250 feet in Pushmataha County near Rattan. Its name may derive from the blackjack oak, a tree native to the region and familiar to the Choctaw. The ridge is especially remembered for the wild mustangs that long roamed there, often connected in local tradition to horses left by early Spanish explorers and later known by the mid-nineteenth century as Choctaw ponies. Blackjack Mountain also became part of Choctaw Nation land after the Louisiana Purchase and the forced westward removal of the Choctaw in 1831, tying it to the broader history of Indian Territory.