Cliffs of Dawn
From Tar Valon Library
The Cliffs of Dawn are a series of impassable cliffs, ranging from one hundred to five hundred feet in height, topped mountain ranges of varying heights, running between the Aiel Waste and Shara, from the Mountains of Dhoom in the north to the Great Rift, about two hundred and fifty leagues south.
(Reference: TWoRJTWoT, Ch. 15)