McAllister C-5 Nebula

The McAllister C-5 Nebula was the location of a conflict between the Cardassian Union and United Federation of Planets in the 24th century. The nebula held a Cardassian fleet which was faced down by the crew of the USS Enterprise under the command of Edward Jellico. William Riker, flying a shuttlecraft, managed to plant mines on the outside hulls of the Cardassian vessels; this was used to force the withdrawal of Cardassian forces from the nebula and forced the Cardassians to release prisoner of war Jean-Luc Picard. (TNG episodes: Chain of Command)

In 2409, another USS Enterprise conducted research at the McAllister C-5 Nebula. However, scans revealed quantum singularities which hinted at the presence of Species 8472 in the area.