Cambridge is the main city and administrative centre of Cambridgeshire.
In Oxford Advanced Learner’s Dictionary, I think the appropriate definition may be:
belonging to something; being part of something: relating to something example (1): a member of the team
used to say what somebody/something is, consists of, or contains example (2): a city of Dublin
I think the appropriate definition for that sentence should be 2, but example (2) make me feel uncertain.