The Columbia River Sahaptin people, also known as the Umatilla people, are a of Native American peoples located along the Columbia River in northeast Oregon state. They reside on the Confederated Tribes of the Umatilla Indian Reservation.

They call themselves Ni Mii Puu, meaning simply "the people", or "we the people".

They offer Umatilla language classes plus a dictionary of the Umatilla language is now available. Today, speakers of all levels speak Umatilla and Northeast Sahaptin (Walla Walla). The Umatilla language is the southern Sahaptin dialect and the Walla Walla is the northeast dialect of Sahaptin. They created a series of videos of the Umatilla language. Watch them on YouTube.

Weyíiletpuu is a dialect of the Nez Perce language as used by the Cayuse people. A distinctive dialect of the Cayuse people has not been used since the 1940’s and is designated as extinct.

The Cayuse (Nez Perce), Umatilla (Columbia River Sahaptin), and Walla Walla (Northeast Sahaptin) were confederated under the Treaty of 1855, yet each one maintains a distinct heritage and unique identity.

The Columbia River Sahaptin have a lot in common with the Nez Perce, Tenino, Northeast Sahaptin, and the Yakima in that they all shared cultural traditions centered around salmon.

The Sahaptin word for the Columbia was "Nch'i-Wana," the "Great River." Today, the river and its salmon continue as a crucial focal point for cultural traditions and the entire region. Salmon feasts and ceremonies have taken place next to the Columbia River for thousands of years.

To call salmon a staple of the tribal diet would be an understatement. Historically, the typical tribal member ate almost a pound of salmon every day, but salmon represented much more than a source of nutrition. It also shaped their society and religion.