Overview
The northernmost part of our world is covered by a vast, snow-white continent marked with many anomalies. It is difficult to verify observations of particular land features here, since the terrain is so dangerous and confusing as to inhibit any explorer. Many names have been given to this land, with High Boros ("boros" means "north" in the Cold Tongue) being most common, though it varies in form (Hi-Boros, Hy-Bora, Hibore, Hybrea, Hyborre, and so on). Telchuria (after the Oeridian god of winter) was a popular appellation given this area by explorers from the Great Kingdom in its heyday, and it, too, seems suitable. Icebergs (islands of ice) seen in the Dramidj Ocean and the Icy Sea undoubtedly once broke off from the fringes of this arctic land.
Several explorers say that a single, unwinking light shines high over the northern pole itself like a sun, above a great circular valley with a tropical interior, but these reports differ on specifics, except that they agree that beasts long believed extinct inhabit this valley. Several regions of vulcanism have been discovered at the top of the world, with many high mountains, great crevasses, and howling blizzards. Frost giants, white dragons, and other predictably cold- dwelling creatures are said to inhabit this land. Human inhabitants have been reported in a barbaric condition, warring with all of the above and some humanoid tribes as well. Demi-humans are unreported, except for a curious note about gnomes or dwarves living underground in one mountainous region.
The size of this arctic continent is unknown, and its outlines are unfortunately vague, as no expedition has ever circumnavigated this land. A huge bridge of ice is said to link this continent to Oerik in the far west, reaching to the largest mountain range on Oerik and the world (about which more later). A second, smaller bridge of ice appears to link the Flanaess's Land of Black Ice with High Boros during the long winter night. It appears that most or all of High Boros lies above 60 degrees north latitude. Assuming that the outer edges of this icy land melt and shrink in the arctic summer's long day then grow wide again during the dark, frigid winter, the total area of High Boros could vary from five million to ten million square miles-respectable enough to count it as a true continent, assuming it has solid rock somewhere beneath its ice and snow.
— Master Cartographer Jawan Sumbar
Guildmaster of Cartographers, Free City of Greyhawk
from An Inspection of the Nature of Oerth