I think Washington is a dense and unique location for fallout 4 as it is borderline by Canada and has the pacific coast and not far to the north west is Alaska which has already fallen into the time line series of events, it be cool to visit all of these place. oh and i almost forgot! Seattle could be a cool experience who knows there could be a new faction there! and there could be awesome sea coastal towns. the best part of all, for all of you who hate twilight, forks Washington could be a giant crater [ forks is the town in which twilight takes place in]. also there would be more NCR to the south and there could be raiders and legion remnants in Montana and if you look at the new vegas plot, the legion was to the north as the NCR was in the west south. actually i dont really know, it might have been an east to west type of ordeal. the dlc could have so many possibilities. anyways what are your ideas? let me know

I've actually suggested a few times the next Fallout should take place in the northwest territory near Oregon/Washington/Canada or perhaps a bit more up north. Fallout could use more of that nuclear winter. Besides that, we need one of the newer Fallout games to take place in the Midwest.

We actually have an http://www.gamesas.com/topic/1437386-official-future-fallout-locations-suggestions-topic-24/ for suggesting locations for potential new Fallout game, you're welcome to repost this in there.