I used to live in the Northwest, so I know a bunch of these tribes the Salish, Squamish, Tlingit, and Tsimshian. The Northwest Coast tribes have a bunch of good stuff going for them, Civ-wise (totem poles are a very obvious UB candidate, for instance), but the trouble is that most of those tribes are quite small. It'd be weird to just pick one and make a full-fledged civ out of it, ignoring the others (but, of course, also weird to make a blob out of them).
what about "the salish"? i saw that kind of generalization based on language if i am not mistaken.