Probably many foreigners interested in Japan know a city called Kanazawa, but not so many of them know which prefecture it belongs to. There are 47 prefectures in Japan and many of them have same name of prefectural capitals.
For example, Osaka prefecture is Osaka city, Kyoto prefecture is Kyoto city and Hiroshima prefecture is Hiroshima city. Then, of course there are cities which are not same as its prefectures. These samples are Nagoya which belongs to Aichi prefecture, Kobe belonging to Hyogo prefecture and Naha belonging to Okinawa prefecture.
Kanazawa belongs to Ishikawa prefecture which is located at Hokuriku region. In general Ishikawa is not known to Japanese so much due to there is no municipality called Ishikawa in the prefecture. Then, another possible reason is that Ishikawa is a merger of former two provinces, Kaga and Noto which are quite famous in Japan. Then, still people are using these province names.
Ishikawa is named after from the largest county existed in Kaga province. Actually when the province was abolished and turned to prefecture in 1871, the prefecture was called Kanazawa. However, when the prefectural capital moved to Mikawa town in Ishikawa county, the name changed to Ishikawa prefecture. Eventually the capital moved back to Kanazawa next year but the name of the prefecture was kept as Ishikawa.