LOCATED MIDWAY BETWEEN the east and west coasts of the United States and just south of the geographic center of the United States in Kansas, Oklahoma is 1 of the Great Plains states. The name comes from the Native American Choctaw language as okla meaning “people,” and humma meaning “red.” Despite images to the contrary, Oklahoma has a unique geography that serves as a transition zone between the forested mountain woodlands of the east and the deserts and mountains of the west. The land rises gently from 207 foot (87 meter) above sea level in the extreme southeast to 4,973 foot (1,516 meter) above sea level at Black Mesa in the northwestern corner in an area known as the Panhandle. Oklahoma offers a variety of features, from grassland plains in the west to forests and mountains in the east. Most of the state is a great, rolling plain, sloping gently from northwest to southeast. Although the region is considered part of the Great Plains, Oklahoma has 4 mountain ranges: the Ouachita in the southeast, the Boston in the northeast (part of the Ozark Plateau that runs across northwestern Arkansas and Missouri), the Arbuckle in the south-central part of the state just north of the Texas border, and the isolated Wichita in the southwest. Approximately 24 percent of the state’s total area is forested, generally in the mountainous regions along the Missouri and Arkansas border. Throughout the northwest and the Panhandle are sudden outcrops of sandstone and gypsum, sharp ravines, and stark hills. The Panhandle may be 1 of Oklahoma’s most recognized map features; that strip of land in the northwest that extends west from the main body of the state as if it were pointing at something. In the north-central region there are several salt flats near the border with Kansas. The largest of these, the Great Salt Plains, covers about 25 square miles (65 square kilometers) near the city of Cherokee. Oklahoma is bordered by Colorado and Kansas in the north, by Texas in the south, by Missouri and Arkansas in the east, and by New Mexico and Texas in the west. With a total area of 69,956 square miles (181,186 sq kilometer) the state ranks 18th nationally in terms of size, including 1,137 square miles of water. Oklahoma’s estimated resident population at the end of 2003 was 3,511,532, ranking 27th nationally. Because 41 percent of the state’s population lives in the 10 largest cities, the state feels incredibly open and free. Oklahoma City, with a population of 523,303, is the state’s largest city and capital, while Tulsa, with 387,807 people, is the state’s other major metropolitan area. The state has a number of important rivers, but the 4 major rivers are the Arkansas, Red, Canadian, and Grand (or Neosho). The Red River also forms the state’s southern boundary with texas. The other significant rivers and streams, all flowing into either the Arkansas or the Red, are the Illinois, Verdigris, Poteau, Canadian, Cimarron, Salt Fork of the Arkansas, and the Washita. Several of the larger rivers in the eastern half of the state have been dammed creating a number of large lakes. Largest of the more than 60 such reservoirs are Eufaula, Texoma, the Grand Lake O’ the Cherokees, and Robert Kerr. Most of Oklahoma has a warm, dry climate. The northwestern part of the state is cooler and drier than the southeast. Precipitation varies greatly throughout the state. Annual average precipitation ranges from 50 inch (128 centimeter) in the southeast to 15 inch (38 centimeter) in the western Panhandle. Snowfall ranges from 2 inch (5 centimeter) a year in the southeast to 25 inch (63 centimeter) in the northwest; the Panhandle receives the most snow.