The location of the Interior Plateau in North America is between the Rocky Mountains and the Pacific Coast Ranges.

The northern region is largely wooded, except in lowland and more southerly areas which resemble the sagebrush grasslands which typify the southern part of the plateau in the Columbia drainage.

At the Lind Coulee Archaeological Site in east-central Washington, leaf-shaped projectile points and knives date between 8500 and 5500 BC.

Based on archaeological evidence, it is suggested that these people were hunters, subsisting also from fishing and plant gathering.

The Cascade phase took place from 7100 to 4300 BC, and was marked by a slight change in toolkit technology from the Windust peoples.

The Late Period, dated to about 2500 BC, the pithouse (quiggly hole) came into existence, such as those at the Keatley Creek Archaeological Site.