From WoWWiki

Lethlor Ravine is a wide craggy valley located in the eastern Badlands. It is populated with whelps and drakes from the Black Dragonflight, and contains several crystalline obelisks that are part of a quest chain.

Subzones of Badlands
Agmond's End • Angor Fortress • Apocryphan's Rest • Camp Boff • Camp Cagg • Camp Kosh • Camp Wurg • Crypt • Dustbelch Grotto • The Dustbowl • Dustwind Gulch • Hammertoe's Digsite • Kargath • Lethlor Ravine • The Maker's Terrace • Mirage Flats • Valley of Fangs