I feel that:
Elsweyr-India
Cyrodil- Rome
Skyrim- Eastern Europe
Black Marsh- This one is hard. The landscape I feel could be closely related to South America, but too little is known of their culture.
Hammerfell- Africa.
Morrowind- Morrowind.
Valenwood- Pre-Colonial America. I've actually been getting into the Bosmer a bit over the past few days, and this is the closest I can mark them.
Summerset Isles- I can't really really say for the land, though people remind of Germans. Haughty, proud, and they even have Nazis.