The Soltoth Caverns were an underground volcanic region deep within the Romulan homeworld. The caverns were inaccessible by foot and required the use of a Transporter in order to enter the underground region. The area was home to the Soltoth Command Post, a bunker facility that dated before the Earth-Romulan War and to the time when the young Romulan Star Empire fought the Hiram Assembly. At first, the Romulans were losing the conflict with the enemy entering the outskirts of the Romii system. It was decided that the Soltoth Command Post would serve as the command and control base for the Star Empire where it would direct the Imperial Romulan Fleet against its enemies. However, the war never reached Romulus itself and the caverns were abandoned.