Korriban

Korriban, known as Pesegam during the reign of Xim, was the sole habitable planet in the Horuset system, located across the galaxy from Koros Major. It was the original homeworld of the Sith species and a sacred planet for the Sith Order, housing the tombs for many ancient and powerful Dark Lords of the Sith, and containing immense dark side power.
After the Hundred-Year Darkness, the remaining Dark Jedi interbred with the Sith species and ruled the Sith using their Force powers. After the Great Hyperspace War, Korriban was abandoned and became a barren world. It was the site of a Sith Academy, and became the headquarters of the One Sith.
It was close to Bosthirda and was located on the Nache Bhelfia and Kamat Krote hyperspace lanes.