For the former inhabitants of this planet, please see Triannon.

Triannon was an inhabited planet located in the Muratas Star Cluster in the Delphic Expanse; it was home to the Triannon people. It was located 6.3 light years from the 12th Sphere.

From the 2050s, Triannon was wracked by a religious war. This war finally ended in March of 2153, but at a terrible cost. Both sides were decimated, all the major cities were destroyed. Millions of Triannons were killed. (ENT: "Chosen Realm")

Triannon homeworld

A non-devastated Triannon from a deleted scene

In the final draft script of "Chosen Realm", the devastated surface of Triannon shown in that episode was referred to as the planet's capital city.
A deleted scene contained a picture of the surface of Triannon before destruction hit.
According to and the Star Trek Encyclopedia (4th ed., vol. 2, p. 418), Triannon was a M-class planet.