GameInformer has just released this http://www.gameinformer.com/p/dishonored_world_map.aspx, revealing a lot more about the world of Dishonored. Turns out it's an entirely fictional world, where an industrial revolution on a set of islands is being fuelled by the blubber of leviathan tentacled beasts named Whales. Apparently the game will take place mostly in the capital city of Dunwall, which is only a small part of the islands, which themselves are an absolutely tiny part of the world as a whole (there's also an absolutely massive, mostly unexplored, continent). Definitely a lot of room for sequels, spin-off, adaptations, etc.