The area of space surrounding the Mephout system was explored between 1000 BBY and 25 BBY. Shortly after the acquisition of the planet Ukio by the Commerce Guild during the Clone Wars, the Mephout system was featured on a galactic map displayed on a viewscreen at a facility run by Passel Argente, the Magistrate of the Corporate Alliance.
The extragalactic Nagai raiders successfully assaulted the Mephout system in 4 ABY as part of an attack on the government of the Mephout Dominion. The Mephout system's population around 25 ABY numbered between ten million and one hundred million.
The Mephout system was first mentioned in the 2009 reference book The Essential Atlas, written by Daniel Wallace and Jason Fry, which placed it in grid square H-20. The Clone Wars: Act on Instinct, a webcomic authored by Pablo Hidalgo and released on StarWars.com over the span of the 2009–2010 second season of the Star Wars: The Clone Wars television series, featured the first appearance of the system.
The Mephout system was first mentioned in the 2009 reference book The Essential Atlas, written by Daniel Wallace and Jason Fry, which placed it in grid square H-20. The Clone Wars: Act on Instinct, a webcomic authored by Pablo Hidalgo and released on StarWars.com over the span of the 2009–2010 second season of the Star Wars: The Clone Wars television series, featured the first appearance of the system.
- The Essential Atlas
- Star Wars: Edge of the Empire Core Rulebook
- The Official Star Wars Fact File Collector's Guide & Galaxy Chart
- Star Wars: Age of Rebellion Core Rulebook
- Star Wars: Force and Destiny Core Rulebook