Trammen, a planet within the Harron sector, was a densely inhabited world situated in the Expansion Region. Located along the hyperspace route known as the Ootmian Pabol, it belonged to both the Galactic Republic and the Exploitation Region controlled by the Grand Companies, which were trading groups, at the time when the Alsakan Conflicts began. During the Galactic Civil War, the Galactic Empire utilized Trammen as a staging ground.
Within the Harron sector and the Slice area of the Expansion Region, Trammen was a terrestrial world found in the Trammen system. Its location on the hyperspace route called the Ootmian Pabol connected it to the Chanosant system and the Belasco system of the Belasco sector.
By 17,000 BBY, Trammen had become a part of the Galactic Republic. Around that time, which marked the beginning of a series of conflicts between the planet Alsakan, the Republic's capital world Coruscant, and their respective allies, Trammen existed within the Exploitation Region, a territory under the active influence of the Grand Companies—trading organizations with Coruscant affiliation that were based along the Spin, the Core Worlds hyperlane. The Ootmian Pabol segment containing Trammen was also under Coruscant's jurisdiction.

Trammen, a densely populated planet, functioned as a staging location for the Galactic Empire during the Galactic Civil War. Soon after the Battle of Yavin, every line squad in the Imperial Army stationed on Trammen had been fully equipped with light repeating blasters. This detail was later documented by Rebel Alliance historian Major Arhul Hextrophon in a compilation of Imperial records for Supreme Commander Mon Mothma and other Rebel officers.
The Imperial Sourcebook, written by Greg Gorden in 1989 and released by West End Games for Star Wars: The Roleplaying Game, was the first mention of Trammen. Subsequently, The Essential Atlas reference book from 2009 placed the Trammen system, and consequently Trammen itself, within grid square O-11.
- Imperial Sourcebook (First mentioned)
- " Twinkle, Twinkle Little Star, How I Wonder Where We Are " — Voyages SF 13 (Unlicensed)
- Imperial Sourcebook, Second Edition
- The Essential Atlas
- Star Wars: The Essential Atlas Online Companion on StarWars.com (article) (backup link)
- The Essential Guide to Warfare
- Star Wars: Force and Destiny Core Rulebook