The archaeology of Iowa is the study of the buried remains of human culture within the U.S. state of Iowa from the earliest prehistoric through the late historic periods. When the 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 visited Iowa, American Indians were largely settled farmers with complex economic, social, and political systems. This transformation happened gradually. 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. 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 increase on the reliance on agriculture and social complexity, with increased use of mounds, ceramics, and specialized subsistence. During the Late Prehistoric period (beginning about AD 900) increased use of maize and social changes led to social flourishing and nucleated settlements. The arrival of European trade goods and diseases in the Protohistoric period led to dramatic population shifts and economic and social upheaval, with the arrival of new tribes and early European explorers and traders. During the Historical period European traders and American Indians in Iowa gave way to American settlers and Iowa was transformed into an agricultural state.[1]