The Cestus system borders the Federation and Gorn Hegemony. With four planets the system is a strategic staging area between the two governments. It was known to the Gorn as the Eliar system. (TOS: "Arena", TNG novel: Requiem) The Cestus system was 400 light-years from the Sol system. It was about 35 light-years, in a spinward direction, from the Delta Triangle. (Star Trek Star Charts)