Starbase 39-Sierra
Starbase 39-Sierra was a Federation starbase. This base was located in the Beta Quadrant.

In 2259, the location of this starbase was labeled on a stellar cartography chart that was seen on the 's ready room viewscreen. () 

In 2364, the helmsman of the , Geordi La Forge, suggested the  could deliver their late-20th century passengers at this starbase. It was five days away, at warp 8, from the position of the Enterprise-D at the edge of the Romulan Neutral Zone in Sector 30. According to La Forge, it would reduce their travel time back to Earth by months. Additionally, Captain Picard thought the extra time would allow them to better acclimate to the 24th century. ()

In 2399, the location of Starbase 39-Sierra was labeled on a Federation star chart that was in Fleet Admiral Kirsten Clancy's office at Starfleet Headquarters. This base was in or near to space claimed by the Romulan Free State. () 

In 3190, the location of this starbase, identified as Starbase 39, was labeled on a star chart used by Commander Paul Stamets for tracking the movement of the Dark Matter Anomaly through the galaxy. ()

Appendices

Background information 

According to Star Trek: Star Charts (p. 66, "United Federation of Planets I") and Stellar Cartography: The Starfleet Reference Library ("Federation Historical Highlights, 2161-2385"), Starbase 39-Sierra was located in the Kaleb sector.

Apocrypha 
The Star Trek: Typhon Pact  Rough Beasts of Empire also mentions the starbase, placing it in the  in the . Starbase 39-Sierra was prominently featured in the game Star Trek Online, in which it served as a hub for Federation missions along the Romulan Neutral Zone.

External link 
 

bg:Звездна база 39-Сиера
cs:Základna 39 - Sierra
de:Sternenbasis 39-Sierra
es:Base Estelar 39
fr:Base stellaire 39-Sierra
ja:第39宇宙基地シエラ
nl:Sterrenbasis 39-Sierra
0039-Sierra, Starbase