The only mention of the Irradiated Great (Desert?) North is in The Pitt, where Ashur talks about a place called "Ronto", which is supposed to be post-nuclear Toronto. Althouh thats a bit silly, because I live pretty close to there, and we would never pronounce it anywhere close to that
There was also a lady in Fallout 2, Marge LeBarge, born in pre-war Canada close to the lake of the same name. But she mentions nothing else besides that, pre-war national distinctions are pretty much moot in Fallout.