Vancadia, also known as Chrellkan III, was the third planet in the Chyrellkan system of the Chyrellkan Sector. It was colonized by humans from Chyrellka, who became known as Vancadians. The Chyrellkans promised the Vancadians full independence in an agreed upon amount of time, but Klingon infiltrators took over the Vancadian government and provoked the people to revolt, seeking independence prematurely. However, in 2269 James Kirk and crew exposed the Klingon plot and the war was averted. The incident persuaded some Vancadians to encourage their people to join the Federation. (TOS novel: Renegade)
- It has never been confirmed whether or not Vancadia eventually joined the Federation.