Kilrah Sector is the home sector of the Kilrathi and the former Kilrathi Empire. Kilrah Sector is anti-spinwards of Sol Sector and takes its name from the Kilrah system. Kilrah Sector consists of the Kur'u Caxki, Kur'u'khag, Kur'u-Pak and Kur'U'Tak Quadrants.
The Kilrah Sector was home to the Kilrathi homeworld of Kilrah, and thus was once one of the most densely-populated and heavily-defended sectors of the Kilrathi Empire. So fearsome were their forces and numbers that the Terrans were never able to successfully stage an attack on the Kilrathi homeworld for the majority of the Terran-Kilrathi War. Thus, the Kilrah Sector was one of the most secure sectors of known space.
The Kilrah Sector bore witness to a series of the first truly successful Terran incursions starting in 2668, when the Terrans deployed their Wake-Class Escort Carriers, among them the famed TCS Tarawa against Kilrathi infrastructure. These attacks could have proven to be the demise of the Empire had it not been for the damaging effects of the Battle of Earth on the Terrans. In 2669 however, the Terrans successfully penetrated the Kilrah System by means of a covert wing of elite pilots who delivered the Temblor Bomb to Kilrah, completely destroying the Kilrathi homeworld and ending the dominance of the Kilrathi Empire.
By 2681, a relative peace had settled between the Terrans and the Kilrathi, and the Terrans were free to travel through the Kilrah Sector largely unopposed. During this same year, however, the Nephilim emerged and launched an invasion by means of a wormhole gate in the Kilrah System. The Terrans fought a long and costly campaign to isolate the invaders as they swarmed through the Kilrah Sector, and were eventually successful in liberating the Kilrah System.