Kōka is a city in southern Shiga Prefecture, Japan. As of 30 September 2021, the city had an estimated population of 89,619 in 36708 house…Kōka is a city in southern Shiga Prefecture, Japan. As of 30 September 2021, the city had an estimated population of 89,619 in 36708 households and a population density of 190 persons per km². The total area of the city is 481.62 square kilometres.