A prefecture is kind of like a city, but usually smaller. It is a district within a city or sovereign nation and is found in both the real world as well as many fictional settings. Japan for example, has many districts divided up by prefectures such as Gunma, HokkaidÅ, Miyagi, Okayama, Osaka and Tokyo. The ruler of a prefecture is called a Prefect.
In the continuity of the Planet of the Apes television series, many of the districts featured in the futuristic Ape City were prefectures. One of which was Chalo prefecture, which was a human settlement administered by a chimpanzee named Veska. [1]
In the Star Trek franchise, the Federation starship USS Yamaguchi was named after Yamaguchi Prefecture. [2]