The Nekrit Expanse was a large nebula-like region located in the Delta Quadrant. The USS Voyager crossed the Expanse in 2373. (VOY episode: "Fair Trade"; ST reference: Star Charts) Because of its vast size, the Expanse functions as a natural barrier, limiting contact between species on either side of the cloud. This accounts for the limited exposure of cultures on the far side (defined relative to Galactic Centre) to many of the technologically superior species on the near. These include such powers as the Borg, the Voth, the Etanians, and the Krenim, which would otherwise be able to wrest control from the ruling nations across the Expanse - the technologically primitive Kazon and the disease-stricken Vidiians. (VOY episode: "Fair Trade")