Mephil Trantos was an Orion base that existed in the 24th century. It was constructed from starship fragments, old space station parts and other components. The base was headed by Kestralnamen and features several dining establishments and gambling facilities.

In 2372, when Quark informed Benjamin Sisko of Mephil Trantos' location, Sisko took the USS Defiant to the Orion base. Sisko's mission to Mephil Trantos was to determine who had sold defective replicators to the Bajorans. Sisko and Quark later discovered that the Orion Calculanthra was the seller of the replicators after Quark beat Calculanthra in a game of dabo.

While on the Orion base, Quark bought several items of contraband and had them delivered to Deep Space 9. (DS9 novel: Wrath of the Prophets)