Starbase Trailer Twenty-Nine was a Federation starbase administered by Starfleet in the mid-24th century.
In 2364, Commander Samuel Freedle, stationed at the starbase, received an order from Commodore Richard K. Berman from Starfleet Command concerning the Romulan Neutral Zone patrol schedule.
At the end of that year, Data read these orders and several others to investigate claims of a conspiracy among the highest members of Starfleet Command. (TNG: "Conspiracy")
The base was never mentioned in dialog; this name came from a mission order.