Hemet is a city in the San Jacinto Valley in Riverside County, California, United States. It covers a total area of 29.3 square miles (76 km2), about half of the valley, which it shares with the neighboring city of San Jacinto. The population was 89,833 at the 2020 census. It borders San Jacinto to the north, East Hemet to the east, Polly Butte and Diamond Valley Lake to the south, and Green Acres to the west.