'Randland' - Lands of the Wheel of Time
This peninsuar features in the book by Guy Gavriel Kay called 'Tigana' (1990) which apparently is based on Renaissance Italy. The book was intended to be an 'adult' fantasy, not in the sense that it was pornographic but that it addressed deeper themes than many more 'childish' fantasy novels and in fact more personal themes too, for example one character was sent to assassinate a ruler and ended up becoming his consort and finds as the years pass that she is unable to kill him. The peninsula is invaded by two forces from the East and the West who divide the various provinces between them and the island province of Chiara (the name itself is reminisicent of Italian names) becomes a neutral province between them. The emphasis on small states rather than vast empires is also seen as a parallel to the Italian city states of the Renaissance. There are fantastical elements too as sorcerors on the peninsula can gain extra powers by cutting off their two middle fingers so their hand resembles the peninsula. After the worlds of J.R.R. Tolkien and C.S. Lewis, Kay's work has probably received the most academic attention. This website has links to a number of academic writings on the background to the setting and their relationship to our history: http://www.brightweavings.com/books/tigana.htm What I like about this landscape is that it is finite and so this allows attention to political detail that is hard in books with vast empires (which in reality probably would have fragmented quickly given the slow speed of most communication forms in fantasy novels) and so to bring the story to a human level.
World of Conan
The Thule Society turns up in fantasy stories featuring the Nazis such as 'Hellboy'; the movie of which starts off on an island supposedly off the coast of Britain. Post-medieval references to Thule may stem from Viking settlements on Greenland which died out when the climate became colder in the 11th century. This is a nice historic map I found of Thule but I cannot find the full one on the internet to show the context:
The Lands of Barsaive