The Luiseno were the original inhabitants of the San Jacinto Valley and had many villages there. The Anza Trail, one of the first European overland routes into California, crossed the valley in the 1770s, and mission padres named it San Jacinto, Spanish for Saint Hyacinth, and set up an outpost there around 1820.
More about San Jacinto
In 1883 the San Jacinto Land Association laid out the modern city at Five Points, and the railroad arrived and the city was incorporated in 1888. Agriculture long sustained the local economy, which also benefited from visitors to the nearby hot springs, and in 1923 the city and its residents helped start the Ramona Pageant, now California's official state outdoor play, which they have supported ever since.
On July 15, 1937, San Jacinto was the end point of the longest nonstop flight yet made, when Mikhail Gromov and his crew of three flew 6,262 miles over the North Pole from Moscow in a Tupolev ANT-25, following Valery Chkalov's polar flight to Vancouver, Washington, earlier that year. The two flights gave the Soviet Union two major world records, and the landing site was later commemorated by the fraternal group E Clampus Vitus and Riverside County.
Sources
Wikipedia: San Jacinto, California