Unknown

The Unknown is supposedly all of the dark areas in Gielinor where players can neither travel to nor see. These areas are not connected to the World map and enclose the areas on the map. For example, there is no map area south of the Kharidian Desert and the vast endlessness of these areas are displayed as black spots on the World map.

Future updates
Some of the "unknown" is typically revealed when new parts of the map are revealed during updates. Writing will occasionally appear on it if something is to be created in the area in the near future. It is more or less the end of the RuneScape visible area, until something is constructed there. As of 1 July 2008, the "Unknown" is checkered blue and white on the World map.

On one version of the RuneScape world map, the "Unknown" is covered in clouds that hide the black areas around Gielinor.

Postbag from the Hedge
On an issue of Postbag from the Hedge, Trader Stan revealed that parts of the "Unknown" are really just water.