Greyhawk geography and population

In the Greyhawk universe, the planet [Oerth] has four continents, but only the [Flanaess], the eastern part of the continent of Oerik, is home to "enlightened humanity." Several human cultures co-exist, including Oeridians, Flannae, Bakluni, and Suloise. Villains have been drawn from each of these cultures, in particular the Suloise. The Baklunish and their arch-foes, the Suloise, once fought a devastating war that decimated part of the continent and nearly destroyed both cultures. This war sparked the migration of the Oeridians and Sueloise refugees into the Flanaess, where they displaced or subjugated the native Flannae and founded their own kingdoms and realms.