Deep Space 3

Deep Space 3 is a Federation Starbase constructed in 2328 (and operating without interuption until at least 2375) with the purpose of keeping an eye on the Breen and other species in Breen Space.

In 2375, the station was under the command of Admiral Marcus Holt, who reported making great strides in Federation/Breen relations until the Breen joined the Dominion.

(RPG Game Book: Star Trek Deep Space Nine: Core Game Book (LUG RPG))