Kasumigaura is a city located in Ibaraki Prefecture, Japan. As of 1 July 2020, the city had an estimated population of 40,254 in 15,839 households and a population density of 257 persons per km². The percentage of the population aged over 65 was 32.0%. The total area of the city is 156.60 square kilometres.. The city takes its name from the nearby lake, Lake Kasumigaura.