Starbase 39-Sierra (STO)
From Trekipedia
Myriad Universes: Starbase 39-Sierra
Starbase 39-Sierra was located in the Sierra system, and was the closest Federation outpost to the Romulan Neutral Zone, as well as the headquarters of Starfleet's Romulan Task Force. Following the Hobus supernova and the destruction of the Romulus system in 2387, Starbase 39-Sierra became the base of operations for rescue and relief efforts. In 2409, the starbase was commanded by Admiral T'Nae.[1]