Starbase 173 was a Federation space station in service with Starfleet in the mid-24th century. This starbase was newly established in 2365, and was located in Sector 23, close to the Romulan Neutral Zone. It was under the command of Vice Admiral Nakamura. Captain Phillipa Louvois was assigned to the base as the sector's Judge Advocate General.
That year, the USS Enterprise-D visited Starbase 173 for port call. During this call, a scheduled crew rotation occurred and experimental modules were off-loaded to the starbase. (TNG: "The Measure Of A Man")