According to Dragon #28, Gargauth (called Astaroth there) is "the devil in charge of supervising the activities of devils in the United Sates. This would seem to indicate that the devils find the United States of great importance and stature, for no other nation has a devil of such rank overseeing it. He may also be partially responsible for all the commercial type that Americans are subject to."
That article is considered noncanon, of course, according to the article itself. Still, it's an amusing (if provincial) tidbit.