Kashiwazaki is a city located in Niigata Prefecture, Japan. As of November 30, 2020, the city had an estimated population of 81,836 in 34,883 ho…Kashiwazaki is a city located in Niigata Prefecture, Japan. As of November 30, 2020, the city had an estimated population of 81,836 in 34,883 households, and a population density of 187 persons per km². The total area of the city was 442.03 square kilometres.