COOS Click for ALSEA or SIUSLAW   Coos Territory: Coastal Oregon. Coos Divisions: Hanis and Miluk.   Portals .   Confederated Tribes of The Coos, Lower Umpqua, and Siuslaw Indians Coos, Oregon   Confederated Tribes of Siletz : part of whose membership is Coos Siletz, Oregon Coos Population United States (2010) - 450   C O O S I A N