Khitomer system

Khitomer was the name of a star system located in Klingon Empire space, the location of planet Khitomer, the home of a Klingon colony and outpost that was destroyed by Romulan attack in the 2340s. 

In a reality where the galaxy's races and cultures collapsed into full-scale war in 2364, Khitomer was one of the systems embroiled in the breakdown of diplomacy. Khitomer produced only about a quarter of the resources as the Romulan system, and fell out of Klingon control around the time of that conflict, and was occupied by a Borg fleet.