The Gamma 7 outpost was a Federation outpost located near the Demilitarized Zone. It monitored the activity of the Cardassians and the Maquis.
On stardate 50485.2, the USS Malinche was patrolling near the Gamma 7 outpost when it was attacked and disabled by a group of Maquis raiders led by Michael Eddington. (DS9: "For the Uniform")
This outpost was only mentioned in dialogue.