Can you sue an unincorporated city?

This is not a complete answer but more a clarification. Whenever one takes legal action against a corporation, that action is addressed and served upon the agent of record for that corporation as that agent is known and listed as per the registration of that corporation which such records are usually kept with the Office of the Secretary of State. This is also true for incorporated municipalities. So now to the question of being able to sue an "unincorporated city", if the city is unincorporated and therefore has not registered with the state then there is no recorded agent on file for the entity you wish to take legal action against, and so the real question becomes who do serve notice to?