Mac,
are you at Mt. Kailash, Tibet?
OK, Tul, I think I get your point now. So I was in fact wrong by saying the "IDL" when I should have talked about the 180° longitude line that separates the EH and WH. While all of Alaska is on one side of the IDL, the EH/WH dividing line does put Semisopochnoi Island just to the EH side of that line so it is the easternmost part of the U.S.
