The Westlands refers to the western portion of the main continent. The Westlands extend from the mountain range known as 'The Spine of the World' (sometimes "the Dragonwall") in the east to the Aryth Ocean (which no inhabitant of the Westlands has crossed in centuries) in the west, and from the Great Blight in the north to the Sea of Storms in the south.
Although no scale appeared on the maps in the books themselves, a scale did appear on the world map in the guidebook accompanying the series. The scale on this map suggests that the distance from the edge of the continent on the west to The Spine of the World in the east is approximately 3,000 miles. This concurs broadly with the designers who worked on The Wheel of Time roleplaying game, who suggested a scale of 1" = 400 miles on the colour endpaper maps in the hardback editions of the books. By their calculations Randland therefore measures roughly 3,500 miles from the west coast to the Spine of the World.
A reliable way of measuring the maps emerged in the prequel novel New Spring, which gave the straight-line distance from Tar Valon to the sea south of Tear as 400 leagues (1,600 miles).
Read more about this topic: Arad Doman