A Starfleet deep space station commanded in 2370 by Vice Admiral Marcus Holt, from which the search for the missing USS Hera and Captain Silva La Forge was directed.
Deep Space 3 is a Federation station operated by Starfleet in the later twenty-fourth century. It is never seen on screen and is known only from dialogue.
In the Next Generation episode Interface, set in 2370, Vice Admiral Marcus Holt contacts Captain Picard from the station with the news that the USS Hera, commanded by Geordi La Forge's mother Silva, vanished after leaving on a routine courier run. Holt had sent the Excelsior and the Nobel to retrace its course without result.
The station is mentioned again in Lower Decks, in Terminal Provocations, when Beckett Mariner recalls seeing a dance act perform there.