More than 3,000 years ago, during the Late Archaic period, American Indians in Iowa began utilizing domesticated plants.
The subsequent Woodland period saw an increased reliance on agriculture and social complexity, with increased use of mounds, ceramics, and specialized subsistence.
Iowa is the 26th most extensive in land area and the 30th most populous of the 50 U. The state's capital, most populous city, and largest metropolitan area fully located within the state is Des Moines.
Tribes which arrived in Iowa in the late prehistoric or protohistoric periods include the Illiniwek, Meskwaki, Omaha, and Sauk.
Main articles: New France, Louisiana (New France), French and Indian War, Treaty of Paris (1763), New Spain, Louisiana (New Spain), Treaty of Aranjuez (1801), Louisiana Purchase, District of Louisiana, and Louisiana Territory Iowa was part of a territory known as La Louisiane or Louisiana, and European traders were interested in lead and furs obtained by Indians.
Several natural lakes exist, most notably Spirit Lake, West Okoboji Lake, and East Okoboji Lake in northwest Iowa (see Iowa Great Lakes). Man-made lakes include Lake Odessa, 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 categorised as the Central forest-grasslands transition ecoregion.
When American Indians first arrived in what is now Iowa more than 13,000 years ago, they were hunters and gatherers living in a Pleistocene glacial landscape.
By the time European explorers and traders visited Iowa, American Indians were largely settled farmers with complex economic, social, and political systems. During the Archaic period (10,500–2,800 years ago), American Indians adapted to local environments and ecosystems, slowly becoming more sedentary as populations increased.Iowa has a relatively smooth gradient of varying precipitation across the state, with areas in the southeast of the state receiving an average of over 38 inches (97 cm) of rain annually, and the northwest of the state receiving less than 28 inches (71 cm).The pattern of precipitation across Iowa is seasonal, with more rain falling in the summer months.The Northern, drier part of Iowa is categorised as the Central tall grasslands and is thus considered to be part of the Great Plains.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.Other factors negatively affecting Iowa's environment include the extensive use of older coal-fired power plants, Iowa has a humid continental climate throughout the state (Köppen climate classification Dfa) with extremes of both heat and cold.