Mapping unit in astrography.  Average density: 30 to 40 worlds per subsector.

Subsectors are noted within a sector by their position using the first sixteen letters of the alphabet (A-P).  In addition, they are named and may be called by a variety of synonyms for subsector, including province, cluster, or district.  Imperial convention is to assign numbers to districts (for example, District 268) which are under Imperial protection because they are pending integration into the Imperium.

-IE ld