Arkansas is the 29th largest by area and the 33rd most populous of the 50 United States. The capital and most populous city is Little Rock, located in the central portion of the state, a hub for transportation, business, culture, and government. The northwestern corner of the state, such as the Fayetteville–Springdale–Rogers Metropolitan Area and Fort Smith metropolitan area, is a population, education, and economic center. The largest city in the state's eastern part is Jonesboro. The largest city in the state's southeastern part is Pine Bluff.
Much of the state's lands were formed from sediment washed down the Mississippi River, leaving enormous deltas and vast areas of coastal marsh and swamp. These contain a rich southern biota; typical examples include birds such as ibis and egrets. There are also many species of tree frogs, and fish such as sturgeon and paddlefish. In more elevated areas, fire is a natural process in the landscape, and has produced extensive areas of longleaf pine forest and wet savannas. These support an exceptionally large number of plant species, including many species of orchids and carnivorous plants. Louisiana has more Native American tribes than any other southern state, including four that are federally recognized, ten that are state recognized, and four that have not yet received recognition.