I think that's just Cyrodiil, Skyrim, Hammerfell, and Highrock. Morrowind (which is Tameriel and not Morrowind proper, for the record), Elsweyr, and Blackmarsh have to be different since they're the Furry/Scalie communities.

Not that I follow Elderscroll's Lore strongly or anything. I just play them to kill folks and explore worlds before getting bored.