The archaeology of Iowa is the study of the buried remains of human culture within the 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 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.
Archaeologists have studied the prehistory of Iowa since the mid-19th century, when large American Indian mounds were first observed along the Mississippi. Early archaeologists such as S.V. Proudfit and Theodore Lewis documented large sites such as earthworks, mounds, and earthlodges. Truly systematic recording of Iowa sites began with Charles R. Keyes and Ellison Orr’s surveys and excavations beginning in the 1920s. Documenting hundreds of sites, often just before they disappeared under the plow, Keyes’ and Orr’s work led to the formation of the Iowa Archaeological Survey, the Iowa Archeological Society, and the designation of Effigy Mounds National Monument. After their deaths in 1951, the Survey was disbanded, and their efforts were continued by the University of Iowa’s Department of Sociology and Anthropology, which formed the Office of the State Archaeologist (OSA) in 1959. The OSA maintains an extensive list of more than 23,000 recorded archaeological sites in Iowa, and conducts survey and excavation across the state. Other institutions conducting archaeological research in Iowa include the State Historical Society of Iowa, the Iowa Archeological Society, the University of Iowa, Iowa State University, Grinnell College, Luther College, and private archaeological firms. Professional archaeologists in Iowa are represented by the Association of Iowa Archaeologists. Iowa archaeology grew dramatically beginning in the 1960s with the introduction of Cultural Resources Management legislation that required archaeological survey and excavation at many federal projects in Iowa.