As fish-eaters, the Clatsops believed the salmon to be a divine gift from the wolf-spirit Talapus who created the great fish to save their people from extinction at a legendary time of near disaster. They adhered to strict tradition in honoring Talapus: the salmon was cut only lengthwise from mouth to tail, never crosswise against the spine; its bones always were returned to the waters for renewal. Failure to obey any such sacred edict to harsh punishment including burial alive. The Clatsops also sanctified the spirits of many forest animals and great great storms that lashed their land.

A non-nomadic people, the Clatsops built low-roofed, partitioned lodges of cedar planks, creating strong, permanent dwelling places. Their canoes were also made of cedar logs, first hollowed out by fire, then shaped and finished with stone or bone tools. Food bowls and utility vessels were fashioned from stone, wood, bone and shell. Mats and baskets for gathering and storage were woven of hide, vine, grass, roots and bark.

The Clatsop people had interacted with white men long before their first recorded visits. Whites had come as traders, trappers, woodsman, as well as survivors of shipwrecks. Although the discovery and settlement of the Columbia River ultimately scattered and decimated the Native Americans, they are ingrained in the region's development.