San Jacinto is a city in Riverside County, California, United States. It is located at the north end of the San Jacinto Valley, with Hemet to its south and Beaumont, California, to its north. The mountains associated with the valley are the San Jacinto Mountains. The population was 44,199 at the 2010 census. The city was founded in 1870 and incorporated on April 20, 1888, making it one of the oldest cities in Riverside County.

The San Jacinto Valley is a valley located in Riverside County, in Southern California, in the Inland Empire. The valley is located at the base of the San Jacinto Mountains in the east and Santa Rosa Hills to the south with the San Gorgonio Pass to the north. The average elevation is 1,500 feet (460 m), with the highest points in the foothills south of Hemet and the western slopes of the San Jacinto Mountains. It is home to two cities, Hemet and San Jacinto, and several unincorporated communities. According to the 2020 census, the valley has a combined population of over 190,000 residents, including more than 143,000 residents within the city limits of Hemet and San Jacinto. The valley is also where the story and play "Ramona" was set; the story was written after author Helen Hunt Jackson visited the valley in the 1880s. The valley is also known for being an area of agriculture, which has given way to more urbanized development.