Sector 21835 was an area of space, a sector located somewhere in the galaxy's Alpha or Beta Quadrants, in proximity to the Federation's border with the Klingon Empire in the late 23rd century.
In the year 2293, the starships USS Ahwahnee and USS Springfield were proposed to take part in the Operation Retrieve plan from a start point in sector 21835. Their locations were noted on a chart listing the locations of planned Starfleet ship locations in a range of sectors from sector 21166 to sector 23094. (TOS movie: The Undiscovered Country)
- The Operation Retrieve info was a series of charts created as set dressing by the production artists and decorators, and as such was not all distinctly visible on screen.