Niihama is a city located in the eastern part of Ehime Prefecture, Japan. As of 31 July 2022, the city had an estimated population of 115,824 in 57781 households and a population density of 490 persons per km². The total area of the city is 234.50 square kilometres. It has the third largest population in Ehime, behind the prefectural capital of Matsuyama and the recently expanded city of Imabari.