The Eocho Mountains existed on the planet of Ossus, positioned within the Outer Rim Territories, and were a mountain range. It was rumored that these mountains were full of crystal caves containing valuable kyber crystals. The city known as Knossa sat in the mountains' western region, alongside the Knossa Spaceport, which had been built surrounding Agorn Mountain. A vergence in the Force, called the Eye of Ashlanae, was situated near these two locations and was a common destination for pilgrims.
The Qel-Droma Epics tell the tale of Jedi who survived the Cron Supernova by finding refuge within the Eocho Mountains' caves; these Jedi's offspring eventually became the Ysanna people. The Ysanna maintained a presence near these caves, cultivating the nitrogen-abundant valleys close to the mountains.