Oklahoma City Geography
According to the United States Census Bureau, the city has a total area of 621.2 square miles (1,608.8 km2), of which, 607.0 square miles (1,572.1 km2) of it is land and 14.2 square miles (36.7 km2) of it is water. The total area is 2.28% water. Oklahoma City is located in the Frontier Country region of Central Oklahoma, in the Southern Plains of North America; it is on the tallgrass and mixed-grass prairie section of the Great Plains.
Most of the area consists of gently rolling hills, covered in places by stands of dense, low trees, along with shrubs and many varieties of prairie grasses and wildflowers. Those woodlands, mostly to the north and east of the metropolitan area, are known as the Cross Timbers. They consist of blackjack oak (Quercus marilandica), post oak (Q. stellata), hickory (Carya spp.), and other plant species which become more widespread in the southeastern forests, about 100 miles (160 km) east of the Oklahoma City metropolitan area.
The city is roughly bisected by the North Canadian River (recently renamed the Oklahoma River inside city limits). The North Canadian was once substantial enough to flood every year, wreaking destruction on surrounding areas, including the original Oklahoma City Zoo. In the 1940s the Civilian Conservation Corps built a dam on the river, which reduced its flow for the next 50 years. In the 1990s, as part of the citywide revitalization project known as MAPS, the city built a series of low-water dams, returning water to the portion of the river flowing near downtown. The city also has three large lakes: Lake Hefner and Lake Overholser, in the northwestern quarter of the city; and the largest, Lake Stanley Draper, in the sparsely populated far southeast of the city.
The population density normally reported for the city using area of its city limits can be a bit misleading, as its urbanized zone covers roughly 244 sq mi (630 km2), compared with the rural areas incorporated by the city, which cover the remaining 377 sq mi (980 km2) of the city limits.
Oklahoma City is the second largest city in the nation in compliance with the Clean Air Act (after Jacksonville, Florida).