Hemet is a city in the San Jacinto Valley in Riverside County, California, United States. It covers a total area of 27.847 square miles, about half of the valley, which it shares with the neighboring city of San Jacinto. The population was 78,657 at the 2010 census. Founding of Hemet predates the formation of Riverside County. The formation of Lake Hemet helped the city grow and prosper, and stimulated agriculture in the area. The city is known for being the home of The Ramona Pageant, California's official outdoor play. Started in 1923, the play is one of the longest running outdoor plays in the United States. Hemet has been named a Tree City USA for 20 years by the Arbor Day Foundation for its dedication to the local forest. The city is home to the Hemet Valley Medical Center, a 320-bed general hospital.