mg, you're right that this region (WA, OR, ID and, sometimes Montana and lower BC) is usually designated the "Pacific Northwest," but the name of the Festival is still "Northwest Folklife Festival" and the organization, which is based in Seattle, is
Northwest Folklife and the name of the festival is Northwest Folklife Festival.

It's a good idea to clarify in the first post which country, state, province, etc., a thread pertains to, but it's not always feasible to do that in the thread title. Space is limited there, and it can be confusing to add a word that's, for instance, not part of the name of a festival or gathering.

BTW, to avoid confusion, the NW Folklife Festival is always held on MEMORIAL DAY WEEKEND, which is not always the last full weekend in May.*

*When May has 5 Fridays, Memorial Day weekend will start on the 4th Friday of May.   Memorial Day is always the last Monday in May, but Monday is not normally considered a weekend day.