The Haldeen sector denoted a sector where, following the Battle of Endor in 4 ABY, a crippled Star Destroyer belonging to the Galactic Empire drifted aimlessly for several weeks. Hail Squadron of the New Republic, supported by the New Republic's Alphabet Squadron, was dispatched to pursue this Star Destroyer. Ultimately, these squadrons collaborated to take down the ailing starship.
The 2019 novel Alphabet Squadron, authored by Alexander Freed, marked the initial introduction of the Haldeen sector.