Land

Oklahoma rises gently to the west from an altitude of 289 ft (88 m) at Little River in the southeastern corner to a height of 4,973 ft (1,517 m) at Black Mesa, on the tip of the panhandle. There are four important mountain ranges in Oklahoma which include the Boston Mountains in the northeast, the Quachitas in the southeast, the Arbuckles in the south-central region, and the Wichitas in the southwest. Much of the northwest belongs to the High Plains, while northeastern Oklahoma is mainly a region of buttes and valleys.

The state is drained mainly by the Arkansas River, and the Red River. Within Oklahoma, the Arkansas is joined by the Verdigris, Grand (Neosho), and Illinois rivers from the north and northeast, and by the Cimarron and Canadian rivers from the northwest and west. Washita, Salt Fork, Blue, Kiamichi, and many smaller rivers join the Red River which forms the state’s southern border. There are few natural lakes but many artificial ones, of which the largest is Lake Eufaula, covering 102,500 acres (41,500 ha).