1984 seems to be set in the UK ('Airstrip One', of 'Oceana').
None of the storyline actually takes place in 'Eurasia' or 'Eastasia' or any other part of the world. They don't need to even actually exist for the storyline. Indeed, this itself is a message about controlling a populace via control of information. The rest of the world could have been razed by war, they could be total utopias. The propaganda keeps people from thinking about alternatives.