The L-langon Mountains were a mountain range located on the edge of Vulcan's Forge, on the far side of the desert from the city of ShiKahr, on planet Vulcan. The L-langon Mountains are the general destination for those participating in the kahs-wan.
In 2237, a young Spock prematurely began his kahs-wan when he journeyed across the Forge towards the L-langon Mountains. Once in the foothills, Spock became cornered by a le-matya, only to be saved by his cousin, Selek, and at the expense of his pet sehlat, I-Chaya. (TAS: "Yesteryear")