In World of Warcraft, the continents are divided up into sections known in-game as zones (sometimes called regions). Some of them appear demarcated on the maps, but cannot be reached by players in any obvious way. For the purposes of this site, they will be called closed zones. Many closed zones are completely empty and flat, but some may contain interesting buildings, terrain, etc.

Not all closed zones are completely unreachable by players, although most require some creative use of game mechanics to access. In fact, some zones, such as Old Ironforge, remain accessible to players more than 2 years after the launch of the game, suggesting that they may be viewed by developers as easter eggs. They can be found in the exploration category.

Zones that appear to be demarcated on official maps, but have been described in future expansions can be found in the future zones category. These zones may be opened in the near future and are also mentioned in the coming soon category. It should be noted that many, if not all, closed zones in Kalimdor and the Eastern Kingdoms will either become accessible or destroyed in World of Warcraft: Cataclysm, due to the introduction of flying mounts and the remodeling of terrain to allow for them.

Zones that are not implemented in World of Warcraft and do not appear on the World of Warcraft in-game map are classified as lore zones.