Kaga is a city located in southwestern Ishikawa Prefecture, Japan. As of 1 March 2018, the city had an estimated population of 67,793 in 29054 …Kaga is a city located in southwestern Ishikawa Prefecture, Japan. As of 1 March 2018, the city had an estimated population of 67,793 in 29054 households, and a population density of 290 persons per km². The total area of the city was 305.87 square kilometres.