Starbase 310

From Memory Alpha, the free Star Trek reference

Starbase 310 is a Federation Starbase located on a planet near the Cardassian border.

In late 2370, the USS Enterprise-D picked up Wesley Crusher and Fleet Admiral Nechayev on the starbase, before flying to Dorvan V. (TNG: "Journey's End")

According to Star Trek: Star Charts, Starbase 310 is located in the Alpha Trianguli star system.