Starbase 171 was a Federation starbase in service during the 24th century.
History
In 2370, from his office on Starbase 171, Starfleet Intelligence CO Admiral Allen Trask and Jean-Luc Picard discussed recent events on Hera, which was two days away from the starbase. The USS Enterprise-D proceeded to the base, but Trask took an Aeolus-class scout and met the starship halfway there. (TNG novel: Infiltrator)