Triex is a Federation member world, home of the Triexian race. Triex is ruled by the Triexian Curia, and its highest judicial body is the Supreme Magisterial Authority of Triex. (novel: Articles of the Federation)

Triexian culture is credited with many contributions to Federation science, architecture, mathematics, and the arts.

Widespread ion storms are a natural phenomenon on Triex, making landing by improperly shielded ships and transporter travel from orbit problematic. (NF short story: "The Road to Edos")

The Starfleet Engineering Academy Triex Annex is located on Triex. (TNG eBook: Slings and Arrows: The Insolence of Office)

In "The Road to Edos," it is stated that Triex was not a Federation member as of 2376; however, Articles of the Federation establishes that Councillor Artrin na Yel had served as Triex's representative to the Federation Council since 2374. It is possible this yet is another example of Triexians being confused for Edosians. It is also possible that the Federation Council does not require planetary membership to admit an observer, ambassador or representative to aspects of their sessions.