The Borderlands are a desert area that lies within Kehjistan.
A wasteland that surrounds Caldeum, the Borderlands are among the most savage lands in Sanctuary. Barren yellow sand stretches for miles, and hostile wildlife roams this region. Desert habitation by humans is possible in the Borderlands, but not easy. Mules are of limited use in these wastes as the sands are constantly shifting.
The Borderlands were originally devoid of any but the most hardened (some would say crazed) prospectors until the great military city of Lut Bahadur (literally, "city of the gate") was built to keep the lacuni in their cliff dwellings safely away from Caldeum. Lut Bahadur's solitary watch over the desolate wastes came to an end c. 885, when precious ore was discovered in the region known as the Stinging Winds. The town of Alcarnus was quickly established as the center of all mining in the area, with several other smaller settlements springing up in its wake. When the Dahlgur Oasis was discovered and a third town was erected there, Caldeum's dominance over the Borderlands was complete. The Borderlands could reliably depend on fresh supplies of food and water from Dahlgur's caravans, protected by the might of Caldeum's Dune Guard.
During the rule of Hakan II however, circumstances changed for the worse. He withdrew the support of Caldeum from the wastes, and those who lived there were left to their own devices. Caravans were left vulnerable, and refugees streamed towards the capital. They brought dark tales with them—rumors of a secret cult intent on raising a demonic army. Furthermore, the area suffered from drought. However, the situation was partially alleviated with the coming of the Nephalem, who defeated Belial (who had possessed Hakan), and rooted the Coven out.