The archaeological record of Oceania stretches over one-third of the earth’s surface with the first humans entering Oceania 50,000 years ago and with the last major archipelago settled approximately a.d. 1300. Oceania is often divided into the cultural-geographic regions of Polynesia, Melanesia, and Micronesia, but these divisions mask much variation, and they do not always accurately characterize the historical relationships among Oceania’s populations. Since the 1950s, archaeological researchers have investigated Oceania’s human and environmental past and have focused on colonization chronologies and the origins of different populations, the intensity and spatial scale of interaction between groups, and changes in social complexity through time and space with a particular concern for the development of chiefdoms. Oceanic archaeologists often use historical linguistics, human genetics, and cultural evolution models to structure their research on ancient Pacific island populations.