The map is almost all accessible. The Orc's kingdom is not, and the western coastal cities of Mercia aren't either. But that's about it. Almost everything else on the map is accessible. Plus, there are lots of underground tombs, dungeons and even a whole buried city! If you like big open worlds, this game is incredibly huge! The gameplay is mostly non-linear, and you really can try to go just about anywhere really soon in the game. I've replayed it multiple times to try different characters, and different places to go at different levels, etc. I highly recommend!