Northwest Coast Indian people of Washington and Oregon, U.S. At the time of first European contact, the Chinookwho were in fact composed of several smaller groups, including the Lower Chinook, the Clatsop, the Clackamas, and the Wascolived along the lower Columbia River and spoke Chinookan languages. They were famous as traders, with connections stretching as far as the Great Plains. They traded dried salmon, canoes, shells, and slaves. Chinook Jargon, the trade language of the Northwest Coast, was a combination of Chinook with Nuu-chah-nulth (Nootka) and other Indian, English, and French terms. The Chinook were first described ethnographically by the explorers Lewis and Clark, who encountered them in 1805. Their basic social unit was the clan. Chinook religion focused on salmon rites and guardian spirits, and the potlatch was an important social ceremony. Following a smallpox epidemic in the early 19th century that brought about the collapse of Chinook culture, most of the remaining Chinook were absorbed into other Northwest Coast groups and many were removed to reservations. In 2001 the Chinook gained federal recognition of tribal status. Chinook descendants numbered more than 1,500 in the early 21st century.