Iroquoians become recognizable in the archaeological record of southern Ontario about A.D. 500, with the appearance of Princess Point sites and maize agriculture in the lower Grand River valley. After A.D. 1000, Iroquoians lived in longhouse villages situated in the interior, north of Lake Erie, Lake Ontario, and the St. Lawrence River. This synthesis of the Iroquoian occupation of southern Ontario prior to European contact focuses on origins, settlement patterns, demography, subsistence, and sociopolitical organization. It highlights the significant contributions to Iroquoian archaeology that have been made by government and private consulting archaeologists over the last two decades.