The Flanaess is the eastern part of the continent of Oerik, one of the four continents of the world of Oerth in the World of Greyhawk.

The Flanaess can be broken down geographically as follows: the Baklunish Basin in the northwest, the Furyondi-Veluna and Nyrond in the north, the Thillonrian Peninsula in the northeast, the Sea of Dust in the far west, the Sheldomar Valley in the west, old Ferrond and its southern frontier (including the City of Greyhawk) at the center of the Flanaess, old Sulm and the Aerdy frontier to the east, the old Great Kingdom to the far east, and the Amedio Jungle to the southwest.