[quote=@FalloutJack]
[@Auz] I have kind of a dumb question: Didn't the Legion originally come from the East?  Maybe more Central, but wasn't the point of Ulysses and the Courier that they were mailmen from the West and East?  You could have it that the Legion went back East to reconnct/regroup with territories it was more familiar with.
[/quote]

Caesar himself came from California, but the first tribe he integrated into the Legion came from the Grand Canyon, and their territory goes from the East Bank of the Colorado up to, I think, Denver, with most of their power in Arizona.