- Alykia sector - formerly a prosperous sector further along the Sagittarius arm of the galaxy. Fell to Chaos forces approximately 914-937.M41
- Harkania - a small sector located on the rimward edge of the Carthax sector and ruled by Lady Sector Tullia Welholm-Vayla. The Sector is also home to the Itholik trading fleet, which either controls or ships more than three quarters of the trading between the Carthax and Harkania Sectors.
- Kamal sector - there are strong relations between the Carthaxian and Kamalian Inquisitorial Conclaves, with members of the Kamalian Conclave assisting during the events following the death of Sector Lord Inquisitor Carthax Marcus Grolin.
- Pohl Sector - a prosperous sector coreward of the Carthax sector and home to the hugely influential Rogue Trader dynasty House Hydronus who control a vast trading empire and have Governorship of several worlds.
- Velterax sector - although technically far distant from the Carthax Sector, being located in the Ultima Segmentum, warp slipstreams make passage between Velterax and Carthax exceptionally rapid, and many sources treat the two as if they were neighbours.