Starbase 10

From Memory Alpha, the free Star Trek reference.

Starbase 10 is a Federation starbase located near the Romulan Neutral Zone.

In 2267, the USS Enterprise traveled to this base following its mission to Deneva. Later that year, Commodore Stocker was assigned to command of the base and was transported there by the Enterprise. (TOS: "Operation -- Annihilate!", "The Deadly Years")

This base has also been mentioned in games' reference books (The Triangle Campaign, Starfleet Operations Manual), novels (Pocket TNG: "Red Sector"), and comics (Gold Key TOS: "Sceptre of the Sun"; Peter Pan Records: "The Robot Masters").