The Thule cultural horizon represents a dramatic northward and eastward movement of people, technology and seafaring economies across the Arctic beginning around the first millennium CE. Archaeological data indicates that by roughly 1100 CE Thule-associated groups were present across the Canadian Arctic and Greenland, bringing specialized whaling technology, large skin boats (umiaks), and large winter houses often built with whale bone and sod. Southampton Island, located at the north entrance to Hudson Bay in present-day Nunavut, preserves coastal Thule occupations in the Foxe Basin region; stratified middens and tool assemblages on the island show adaptation to rich marine resources and seasonal mobility.
Material markers that archaeologists use to identify Thule presence include toggling harpoon heads, bipointed foreshafts, large whale-bone or sod-houses, and a toolkit optimized for large-mammal hunting. These innovations appear to have supported rapid demographic expansion into marginal Arctic environments. Archaeological sequences also show interaction with, and eventual replacement of, earlier Paleo-Eskimo traditions such as the Dorset culture in many areas, though the timing and degree of replacement varied locally. Limited evidence suggests that environmental opportunities—sea-ice conditions and access to bowhead and beluga populations—helped shape the pace and routes of Thule dispersal across the eastern Arctic.