Confederated Tribes of Coos Lower Umpqua and Siuslaw Indians Tags: Ethnic Group.The Confederated Tribes of the Coos Lower Umpqua and Siuslaw Indians of Oregon are a federally recognized Native American tribe of Hanis Coos Miluk Coos Lower Umpqua and Siuslaw people in Oregon. They are indigenous peoples of the Plateau. thumbnail language Coosan languages, Siuslaw language, English language, Kuitch_language related Coos people, Siuslaw people, Umpqua people total population 526 Learn more... Loading...