Oklahoma

I

Introduction

Oklahoma, state in the western area of the south central United States. It is bordered by Colorado and Kansas on the north and Missouri and Arkansas on the east. South and west of Oklahoma is Texas, and on the western edge of Oklahoma’s Panhandle lies New Mexico.

Oklahoma is a land of great diversity, a transitional state both physically and culturally. Topographically it varies from the wooded mountains of the more humid east to the sparse and dry country of the western plains. The changing landscape of Oklahoma is reflected in its economic activities, which range from the raising of wheat in western and central areas to the lumbering that is carried on in the Ouachita Mountains in the southeastern part of the state.

The name Oklahoma was derived by combining the Choctaw words for “red” and “people.” Part of the state’s area had been originally put aside for settlement of Native Americans and was known as Indian Territory. The other section of the state, Oklahoma Territory, was gradually opened for white settlement toward the end of the 19th century. Oklahoma earned its nickname, the Sooner State, from the fact that some land-hungry settlers, known as the Sooners, jumped the starting gun that was to open one section of the territory to settlers and rushed in to take land before they were legally entitled to do so.

Oklahoma was admitted to the Union on November 16, 1907, as the 46th state. Resulting from the combination of Indian and Oklahoma territories, the state retains marked features of its Native American heritage in the makeup of its population and the Indian place-names in the state. Oklahoma City is the state’s capital and largest city.

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II

Physical Geography

Oklahoma covers 181,035 sq km (69,898 sq mi), including 3,188 sq km (1,231 sq mi) of inland water, and it ranks 20th in size among the 50 states. Along its southern border, Oklahoma measures 507 km (315 mi). The Panhandle, which is 269 km (167 mi) long, brings Oklahoma’s northern border to 747 km (464 mi). From north to south the length ranges from 267 to 357 km (166 to 222 mi), except in the Panhandle, which measures only 55 km (34 mi). The mean elevation is 400 m (1,300 ft).

Oklahoma has mountainous lands as well as vast areas of level plains. Soils vary from rich black grassland soils to sterile blow sand, and vegetation ranges from sagebrush to grassland to dense forest. The climate varies from semiarid to humid.

A

Natural Regions

Three of the natural regions, or physiographic provinces of the United States extend within Oklahoma’s territory. These are the Coastal Plain, the Interior Highlands, and the Interior Plains. Of these, the Interior Plains make up the greater part of the state, the Coastal Plain and Interior Highlands flanking these plains on the south and east. Elevations in Oklahoma range from under 90 m (about 300 ft) in the southeast corner to 1,500 m (5,000 ft) in the northwest edge of the Panhandle.

The Gulf Coastal Plain forms a narrow strip along the southeastern Texas-Oklahoma border. The Red River Plains, as it is known to some because it parallels that stream, are low, relatively flat, and sometimes swampy.

The topography changes dramatically in the Interior Highlands north of the Coastal Plains where peaks in the Ouachita Mountains reach as high as 800 m (2,600 ft). The Ouachita Mountains, a series of steeply folded ridges and valleys, resemble parts of the Appalachians farther to the east. Ouachita peaks such as Winding Stair, Kiamichi, Blackfoot, and Rich tower 460 m (1,500 ft) above their valleys.

North of the Ouachitas, set apart from them by the valley of the Arkansas River, is the Ozark Plateau, also part of the Interior Highlands. Broad, flat-topped hills are separated one from another by narrow, V-shaped river valleys. Elevations here range from 180 m (600 ft) to 365 m (1,200 ft). Cookson Hill and Boston Mountains are names sometimes attached to this region.

By far the greater part of the state is the Interior Plains province. From east to west the elevation in this region, reaching 600 m (2,000 ft), divides it into the Osage Plains on the east and the High Plains to the west. The Osage Plains are themselves divided into subregions: the central Red Bed Plains and the Prairie Plains (or Arkansas River valley); the hilly sections of the Sandstone and Gypsum hills; the folded limestones, shales, and other strata of the Arbuckle Mountains and the more rugged, chiefly granite Wichitas.

The High Plains, a part of the Great Plains, occupy northwestern Oklahoma and the Panhandle. Elevations on the plains in the western Panhandle exceed those of the mountains farther east. The highest point in the state is located here at Black Mesa (1,516 m/4,973 ft), the remnants of an ancient lava flow.

B

Rivers and Lakes

There are about 500 named creeks and rivers in Oklahoma; many are short, intermittent streams. Most rivers flow across the state from northwest to southeast. Two major tributaries of the Mississippi River drain the state—the Arkansas and Red rivers. The principal tributaries of the Arkansas River are the Cimarron and Canadian rivers from the west, the Verdigris, Grand, and Illinois rivers from the north and northeast, and the Poteau River from the south. As with most rivers that rise on the western plains and flow east, rivers such as the Cimarron and Canadian are characterized by broad, shallow, and sandy channels. In dry season there will be little surface flow, although much subsurface water will flow through the rivers’ sandy beds. The chief tributaries of the Red River are the North Fork, Washita, Blue, Boggy, and Kiamichi rivers. Waterways originating in the more humid eastern regions are characterized by their steep banks, swift current, and depth.

All of the larger lakes in the state are artificial and more than three-fourths of them are in the eastern portion of the state, where the rainfall is greater. These reservoirs were created for flood control, navigation, water supply, power generation, and recreation. The United States Army Corps of Engineers, the Bureau of Reclamation, and the Grand River Dam Authority created the major reservoirs of the state, including Altus, Arbuckle, Canton, Eufaula, Fort Supply, Keystone, Oologah, Texoma, Thunderbird, and Wister. Some of these reservoirs are part of the McClellan-Kerr Arkansas River Navigation System that connect Tulsa’s port of Catoosa to barge traffic on the Mississippi system.

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