Spine of the World

The Spine of the World was a mountain range stretching from the westernmost part of Faerûn south of Icewind Dale to the eastern edge of the Cold Wood where it joined up with the Ice Mountains, which stretched all the way to the Anauroch.

Geography
Folks all across the lands of the Savage Frontier and the Silver Marches, but especially those in Scornubel, referred to the Spine as "the Wall", typically because it was simply an endless, nearly impassable range of high, jagged, perpetually ice-covered mountains, but also because on the winter days when the white snow covered faces of the peaks meet the iron-gray of the sunless winter sky, it appeared as though it was holding up sky.

While the western-most edge of the Spine was penetrated by a circuitous, always dangerous trade route to Icewind Dale, the rest of the range was not even approached by those without a stout heart. Those creatures that did inhabit the Spine were not spoken of in polite company, and their propensity to raid the lands below kept the conifer-cloaked, stag-roamed rolling foothills relatively uninhabited (as though the Savage Frontier and the Silver Marches were packed)―but it should come as no surprise that several fierce barbarian tribes inhabited these lands, traveling between summer and winter camps.

Some of the mountains in this range stood over 20,000 feet tall, and all but the smallest were covered in snow and ice at all times.