The Delta Triangle is a vast uninhabited sector of the Milky Way Galaxy, located three weeks away from the nearest Federation starbase via subspace radio. The Delta Triangle has the unusual ability to cause starship sensors fluctuate in a state of chaos while within the region.
Several decades prior to the 2260s, the Federation starship Bonaventure explored the Triangle, but was trapped within it. Other species that were trapped over the years included Andorians, Tellarites, Klingons, Orions, Vulcans, Romulans, Humans, Phylosians, and the Gorn.
In 2269, the Template:USS surveyed the region, to investigate and possibly determine the cause for the high number of mysterious disappearances of starships that have been recorded there since ancient times.
After nearly falling victim to a mouse trap set by the Klingons, the Enterprise along with the Klingon battle cruiser Template:IKS, became trapped in a pocket dimension of the Triangle known as Elysia. (Template:TAS)