|Agrat-Mot nebula 
||A nebula located in the Delta Quadrant. Located in B'omar territory, the nebula was important in their negotiations with the Nassordin. The B'omar refused permission for Voyager to travel near the nebula when Captain Janeway negotiated for passage through their territory in that year. 
|Alawanir Nebula 
||A nebula located in Federation territory. The USS Enterprise-D conducted spectral analyses of the Alawanir Nebula on several different frequencies whilst travelling to the Gariman system. 
|Arachnid Nebula 
||A nebula which the NX-01 charted in 2151. It was over eight billion kilometres in diameter, though an astronomy book which captain Archer had studied as a child had claimed that it was 6.5 billion kilometres across. 
|Azure Nebula 
||A type 11 nebula on the border between the Klingon Empire and the Federation. Captain Sulu attempted to use the Azure nebula to cross into Klingon space in 2293 so as to rescue Captain Kirk an McCoy from Rura Pente. The attempt was foiled by a Klingon battle cruiser. The Azure nebula contains significant amounts of sirillium gas.