The Doirlon Hills are an upland region located along the eastern border of Illian, at the western edge of the Plains of Maredo. The Illianers have fortified these hills with wooden border forts and stockades as part of their defensive lines against Tear.
In late 999 NE and early 1000 NE, Rand al'Thor assembled a vast army some 200 miles east of the Doirlon Hills in preparation for an invasion of Illian, then the stronghold of the Forsaken Sammael. A large-scale assault was launched on the hillforts under the command of the High Lord Weiramon Saniago. Despite some successes (mostly attributable to the Asha'man who accompanied Weiramon), the attack was checked by the personal intervention of Sammael. At this point Rand, another force of Asha'man, and the Legion of the Dragon Traveled into the city of Illian itself to liberate it. Sammael was forced to abandon the hillforts, which were subsequently overrun by Rand's forces.