Iowa is a state in the Midwestern region of the United States, bordered by the Mississippi River to the east and the Missouri River and Big Sioux River to the west. It is bordered by six states: Wisconsin to the northeast, Illinois to the east and southeast, Missouri to the south, Nebraska to the west, South Dakota to the northwest, and Minnesota to the north.
In colonial times, Iowa was a part of French Louisiana and Spanish Louisiana; its state flag is patterned after the flag of France. After the Louisiana Purchase, people laid the foundation for an agriculture-based economy in the heart of the Corn Belt.
In the latter half of the 20th century, Iowa's agricultural economy made the transition to a diversified economy of advanced manufacturing, processing, financial services, information technology, biotechnology, and green energy production. Iowa is the 26th most extensive in total area and the 30th most populous of the 50 U.S. states. The state's capital, most populous city, and largest metropolitan area fully located within the state is Des Moines. A portion of the larger Omaha, Nebraska, metropolitan area extends into three counties of southwest Iowa. Iowa has been listed as one of the safest U.S. states to live in.
Iowa is bordered by the Mississippi River on the east and the Missouri River and the Big Sioux River on the west. The northern boundary is a line along 43 degrees, 30 minutes north latitude. The southern border is the Des Moines River and a not-quite-straight line along approximately 40 degrees 35 minutes north, as decided by the U.S. Supreme Court in Missouri v. Iowa (1849) after a standoff between Missouri and Iowa known as the Honey War.
Iowa is the only state whose east and west borders are formed almost entirely by rivers. Carter Lake, Iowa, is the only city in the state located west of the Missouri River.
Iowa has 99 counties, but 100 county seats because Lee County has two. The state capital, Des Moines, is in Polk County.
Iowa's bedrock geology generally increases in age from west to east. In northwest Iowa, Cretaceous bedrock can be 74 million years old; in eastern Iowa Cambrian bedrock dates to c. 500 million years ago.
Iowa is generally not flat; most of the state consists of rolling hills. Iowa can be divided into eight landforms based on glaciation, soils, topography, and river drainage. Loess hills lie along the western border of the state, some of which are several hundred feet thick. Northeast Iowa along the Upper Mississippi River is part of the Driftless Area, consisting of steep hills and valleys which appear almost mountainous.
Several natural lakes exist, most notably Spirit Lake, West Okoboji Lake, and East Okoboji Lake in northwest Iowa (see Iowa Great Lakes). To the east lies Clear Lake. Man-made lakes include Lake Odessa, Saylorville Lake, Lake Red Rock, Coralville Lake, Lake MacBride, and Rathbun Lake. Before European settlement, 4 to 6 million acres of the state was covered with wetlands, about 95% of these wetlands have been drained.
Iowa's natural vegetation is tallgrass prairie and savanna in upland areas, with dense forest and wetlands in flood plains and protected river valleys, and pothole wetlands in northern prairie areas. Most of Iowa is used for agriculture; crops cover 60% of the state, grasslands (mostly pasture and hay with some prairie and wetland) cover 30%, and forests cover 7%; urban areas and water cover another 1% each.
The southern part of Iowa is categorized as the Central forest-grasslands transition ecoregion. The Northern, drier part of Iowa is categorized as part of the Central tall grasslands.
There is a dearth of natural areas in Iowa; less than 1% of the tallgrass prairie that once covered most of Iowa remains intact; only about 5% of the state's prairie pothole wetlands remain, and most of the original forest has been lost. As of 2005 Iowa ranked 49th of U.S. states in public land holdings. Threatened or endangered animals in Iowa include the interior least tern, piping plover, Indiana bat, pallid sturgeon, the Iowa Pleistocene land snail, Higgins' eye pearly mussel, and the Topeka shiner. Endangered or threatened plants include western prairie fringed orchid, eastern prairie fringed orchid, Mead's milkweed, prairie bush clover, and northern wild monkshood.
The explosion in the number of high-density livestock facilities in Iowa has led to increased rural water contamination and a decline in air quality.
Other factors negatively affecting Iowa's environment include the extensive use of older coal-fired power plants, fertilizer and pesticide runoff from crop production, and diminishment of the Jordan Aquifer.
