The Barrier Mountains were created long ago, when the Land of Dragons merged with the land of Pirra.When the Shadow Lord arrived in the Land of Dragons, he fled into the mountains after being burned by an Emerald Dragon. There he found followers in the men and women who took refuge in them, and watched both Pirra and the Land of Dragons for weaknesses he could exploit. He also discovered an Ak-Baba egg hidden among the mountains.
The Barrier mountains extend along Deltora's northern border, across the lands of the Ralads, Plains, Mere, and Dread Gnomes. They are inhabited by all manner of dark creatures, including Ooze toads, Bubblers, and Stingers. Bandits and other lawless members of Deltora inhabit the mountains as well.
Despite their proximity to the Shadowlands, a number of settlements are located near the Barrier Mountains. The town of Shadowgate is located at their base, at Deltora's most northern point. Dread Mountain, the home of the Dread Gnomes and Kin, is the largest mountain in the range.