Starbase 375

Star Trek: Deep Space Nine
Episode: DS9 528 - Behind the Lines

Admiral Ross served at Starbase 375, where he uncovered a major reason for the Dominion's bourgeoning stranglehold on the quadrant: a sensor array, which monitored activity across five sectors.

Sisko, following a promotion to the starbase, and thus his subsequent removal from commanding the Defiant, watched Dax lead the ship on a successful mission.

Later, toward the end of the Dominion War, the Seventh Tactical Wing assembled at Starbase 375.