A similar entry appears in the Wheel of Time Companion confirming the information available in the main story arc.
Author: Atarah al'Norahn
Abayan was one of the nations of the Free Era. Abayan was located in the northern part of the Westlands. To the west was the Aryth Ocean, with Basharande to the northeast, Indrahar and Oman Dahar to the east, and Darmovan to the south, with the border following the path of the river Dhagon. Eventually, this area of land became what is now the northern part of Arad Doman.
By FY 963, Abayan had fallen to Hawkwing.
(Reference: The World of Robert Jordan's "The Wheel of Time")