A Sector Group was a formation of the Imperial Navy, defined as the total naval strength available to a sector. Command of a Sector Group was delegated to a high admiral. Usually, "high admiral" was a title granted to the sector Moff; however, in cases where sector naval forces were constantly engaged in operations, the high admiral was a separate position to the Moff to allow the latter to concentrate on running the sector without devoting a disproportionate amount of time on naval matters.
Sector Group HQ included a squadron under the personal command of the Moff, and some Moffs with political connections or proven tactical ability sometimes had more squadrons available to them. On average, a Sector Group was expected to maintain a force of 2,400 starships, including twenty-four Star Destroyers and 1,600 combat vessels.