Oklahoma is situated between the Great Plains and the Ozark Plateau in the Gulf of Mexico watershed, generally sloping from the high plains of its western boundary to the low wetlands of its southeastern boundary. Its highest and lowest points follow this trend, with its highest peak, Black Mesa, at 4,973 feet (1,516 m) above sea level, situated near its far northwest corner in the Oklahoma Panhandle. The state s lowest point is on the Little River near its far southeastern boundary in or near the town of Idabel, OK, which dips to 289 feet (88 m) above sea level. A river carves a canyon in the Wichita Mountains.Among the most geographically diverse states, Oklahoma is one of four to harbor more than 10 distinct ecological regions, with 11 in its borders �� more per square mile than in any other state. Its western and eastern halves, however, are marked by extreme differences in geographical diversity: Eastern Oklahoma touches eight ecological regions and its western half contains three. The Ouachita Mountains cover much of southeastern Oklahoma.Oklahoma has four primary mountain ranges: the Ouachita Mountains, the Arbuckle Mountains, the Wichita Mountains, and the Ozark Mountains. Contained within the U.S. Interior Highlands region, the Ozark and Ouachita Mountains mark the only major mountainous region between the Rocky Mountains and the Appalachians. A portion of the Flint Hills stretches into north-central Oklahoma, and in the state s southeastern corner, Cavanal Hill is regarded by the Oklahoma Tourism Recreation Department as the world s tallest hill; at 1,999 feet (609 m), it fails their definition of a mountain by one foot. The semi-arid high plains in the state��s northwestern corner harbor few natural forests. Oklahoma there is a rolling to flat landscape with intermittent canyons and mesa ranges like the Glass Mountains. Partial plains interrupted by small mountain ranges like the Antelope Hills and the Wichita Mountains dot southwestern Oklahoma, and transitional prairie and woodlands cover the central portion of the state. The Ozark and Ouachita Mountains rise from west to east over the state s eastern third, gradually increasing in elevation in an eastward direction. More than 500 named creeks and rivers make up Oklahoma s waterways, and with 200 lakes created by dams, it holds the highest number of artificial reservoirs in the nation. Most of the state lies in two primary drainage basins belonging to the Red and Arkansas rivers, though the Lee and Little rivers also contain significant drainage basins.
it is fairly flat. there are the Arbuckle mountains in the south, but they are a very small mountain range. the eastern part has some hills leading into the Ozarks in Arkansas, but for the most part Oklahoma is flat.
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