Oklahoma, state in SW United States. It is bordered by Missouri and Arkansas (E); Texas, partially across the Red R. (S, W); New Mexico, across the narrow edge of the Oklahoma Panhandle (W); and Colorado and Kansas (N).

Area, 69,919 sq mi (181,090 sq km).

Pop. (2000) 3,450,654, a 9.7% increase since the 1990 census.
Capital and largest city, Oklahoma City.
Motto, Labor Omnia Vincit [Labor Conquers All Things].
State bird, scissor-tailed flycatcher.
State flower, mistletoe.
State tree, redbud.

The high, short-grass plains of W Oklahoma are part of the Great Plains , which are chilled by north winds in the winter and baked by intense heat in the summer. There are extensive grazing lands and wheat fields. The plains are broken here and there, notably by Black Mesa in the Panhandle and by the Wichita Mts. in the southwest, but the general slope is downward to the east, and central and E Oklahoma is mostly prairie, rising in the northeast to the Ozark Mts. and in the southeast to the Ouachita Mts.

The original 1907 constitution is still in effect. Oklahoma has a legislature of 48 senators and 101 representatives. The governor is elected for a four-year term. The state elects two U.S. senators and six representatives and has eight electoral votes.

Cotton, formerly the leading cash crop of Oklahoma, has been succeeded by wheat; income from livestock, however, exceeds that from crops. Many minerals are found in Oklahoma, including coal, but the one that gave the state its wealth is oil. After the first well was drilled in 1888, the petroleum industry grew enormously, until Oklahoma City and Tulsa were among the great natural gas and petroleum centers of the world. Oil and gas have declined somewhat in importance today.

Many of Oklahoma's factories process local foods and minerals, but its chief manufactures include nonelectrical machinery and fabricated metal products. Military bases and other government facilities are also important.