The East Garrison is located inside Blackrock Depths, and is accessible directly from the Detention Block by a door locked with the Shadowforge Key. If the door cannot be bypassed, it is necessary to enter the Ring of the Law and defeat the challengers there to access the garrison. The garrison holds the gigantic locking mechanism to open the passage to the West Garrison and the Manufactory, but the Shadowforge Key is also needed to operate the lock. The stairs leading up from the East Garrison lead past the Ring of the Law spectators to the Shrine of Thaurissan.
- NOTE** As of Cataclysm, the Shadowforge key is no longer required to open gates or operate the mechanism. If you're trying to solo, don't spend forever trying to get the key, not only will you wonder why the related quest is gone, you'll be disappointed. Lfmf. Just click on the mechanism in the east garrison.