The first houses in the Plateau Culture Area date to around 6,000 years ago. They are fairly small (4-5 meters across), circular, and about a meter deep. By 5000 years ago, housepits are larger and evidence longer or more intensive use as indicated by higher artifact counts and broader artifact diversity.

Ames argues that there were probably structures/houses in the NW Coast area by 5000 years ago. The development of large very deep shell midden suggest sedentary use and thus houses/shelters of some type. Large houses and "towns" are thought to be as old as 3,500 years ago.

Peoples of the Northwest Coast: Their Archaeology and Prehistory July, 2000 by Kenneth M. Ames