|San Jacinto River|
|Cities||Hemet, San Jacinto, Perris, Lake Elsinore|
|Source||San Jacinto Mountains|
|• location||San Bernardino National Forest, Riverside County|
|• coordinates||33°43′52″N116°48′36″W / 33.73111°N 116.81000°W |
|• elevation||2,100 ft (640 m)|
|Lake Elsinore, at the mouth of Railroad Canyon, northwest of the Sedco Hills and west of the Tuscany Hills of the Temescal Mountains, Riverside County|
|33°38′45.06″N117°18′53.42″W / 33.6458500°N 117.3148389°W Coordinates: 33°38′45.06″N117°18′53.42″W / 33.6458500°N 117.3148389°W|
|1,243 ft (379 m)|
|Length||42 mi (68 km), Northwest then southwest|
|Basin size||780 sq mi (2,000 km2) |
|• average||16.4 cu ft/s (0.46 m3/s) |
|• minimum||0 cu ft/s (0 m3/s)|
|• maximum||16,000 cu ft/s (450 m3/s)|
|River system||Santa Ana River basin|
|• left||South Fork San Jacinto River|
|• right||North Fork San Jacinto River|
The San Jacinto River is a 42-mile-long (68 km)  river in Riverside County, California. The river's headwaters are in Santa Rosa and San Jacinto Mountains National Monument.  The lower portion of the 765-square-mile (1,980 km2) watershed is urban and agricultural land. As a partially endorheic watershed that is contiguous with other Great Basin watersheds, the western side of the San Jacinto Basin is a portion of the Great Basin Divide.
The river is formed at the west base of the San Jacinto Mountains by the confluence of its North and South forks. The South Fork flows from near Santa Rosa Summit, through Pine Meadow and Garner Valley to Lake Hemet, which holds 14,000 acre-feet (17,000,000 m3) of water. Hemet Dam was built in 1895 to supply water to the city of Hemet. Downstream of the dam, the South Fork joins the North Fork east of the town of Valle Vista near Highway 74, and the main stem of the San Jacinto River continues northwest until it discharges into Mystic Lake, a couple of miles east of Lake Perris. Overflow from the river then flows southwest, passing under Ramona Expressway and Interstate 215, and through Railroad Canyon to Railroad Canyon Reservoir, also called Canyon Lake, which has a capacity of 11,900 acre-feet (14,700,000 m3). Downstream of Railroad Canyon Dam, the river continues flowing roughly west southwest through the canyon through the Temescal Mountains for about 3 miles (4.8 km) until it drains into Lake Elsinore. The lake usually has no outflow other than evaporation, but in years of heavy rainfall it overflows into Temescal Creek, which flows northwest to the Santa Ana River in Corona, California.
Lake Elsinore is a city in western Riverside County, California, United States. Established as a city in 1888, it is on the shore of Lake Elsinore, a natural freshwater lake about 3,000 acres (1,200 ha) in size. The city has grown from a small resort town in the late 19th and early 20th centuries to a suburban city with over 70,000 residents.
Lake Elsinore is a natural freshwater lake in Riverside County, California, located east of the Santa Ana Mountains and fed by the San Jacinto River. Originally named Laguna Grande by Spanish explorers, it was renamed for the town of Elsinore, established on its northeastern shore on April 9, 1888.
The Santa Ana River is the largest river entirely within Southern California in the United States. It rises in the San Bernardino Mountains and flows for most of its length through San Bernardino and Riverside Counties, before cutting through the northern Santa Ana Mountains via Santa Ana Canyon and flowing southwest through urban Orange County to drain into the Pacific Ocean. The Santa Ana River is 96 miles (154 km) long, and its drainage basin is 2,650 square miles (6,900 km2) in size.
State Route 74, part of which forms the Palms to Pines Scenic Byway or Pines to Palms Highway, and the Ortega Highway, is a state highway in the U.S. state of California. It runs from Interstate 5 in San Juan Capistrano in Orange County to the city limits of Palm Desert in Riverside County. Stretching about 111 miles (179 km), it passes through several parks and National Forests between the Pacific coast and the Coachella Valley.
Area code 951 is a California telephone area code that was split from area code 909 on July 17, 2004. It covers western Riverside County, including the cities and communities of Banning, Beaumont, Corona, Canyon Lake, Riverside, Temescal Valley, Woodcrest, Moreno Valley, Perris, Menifee, Lake Elsinore, Wildomar, Murrieta, Temecula, San Jacinto, Hemet, Lakeview, Nuevo, Norco, Eastvale, Jurupa Valley, and Idyllwild.
Temescal Creek is one of the principal watercourses in the city of Oakland, California, United States.
The Eastern Municipal Water District of Southern California is a regional water district formed in 1950 to secure additional water for a largely rural area of western Riverside County. In addition to water service, responsibilities include sewage collection, water desalination and water recycling.
The Rawson Mountains are a mountain range in Riverside County, California. The Rawson Mountains are located south of the Diamond Valley Lake, southeast of Domenigoni Valley, east of French Valley, west of Goodhart Canyon and north of Bachelor Mountain, Auld Valley and Black Mountain. The Rawson Mountains are composed primarily of metamorphic rock of the Triassic - Jurassic French Valley formation, formed as a roof pendant of the Peninsular Range Batholith. The extreme western end of the range and various intrusions within it are Cretaceous granitic rock.
Coyote Creek is a principal tributary of the San Gabriel River in northwest Orange County, southeast Los Angeles County, and southwest Riverside County, California. It drains a land area of roughly 41.3 square miles (107 km2) covering eight major cities, including Brea, Buena Park, Fullerton, Hawaiian Gardens, La Habra, Lakewood, La Palma, and Long Beach. Some major tributaries of the creek in the highly urbanized watershed include Brea Creek, Fullerton Creek, and Carbon Creek. The mostly flat creek basin is separated by a series of low mountains, and is bounded by several small mountain ranges, including the Chino Hills, Puente Hills, and West Coyote Hills.
Canyon Lake, sometimes referenced as Railroad Canyon Reservoir, is a reservoir created in 1928 by the construction of the Railroad Canyon Dam in Railroad Canyon or in the Temescal Mountains of southwestern Riverside County, California. The reservoir covers approximately 525 acres (212 ha), has 14.9 miles (24.0 km) of shoreline, and has a storage capacity of 11,586 acre⋅ft (14,291,000 m3). It is owned and operated by the Elsinore Valley Municipal Water District.
Railroad Canyon, originally named San Jacinto Canyon, also known as Cottonwood Canyon, and Annie Orton Canyon, is a valley located in Riverside County, California. It encloses the lower course of the San Jacinto River at the point where the river passes south through the Temescal Mountains from a point 6 miles south-southwest of Perris, California, through Canyon Lake, California, then west to Lake Elsinore, California. The canyon has its present name from the California Southern Railroad that was constructed down the canyon in 1882.
Temescal Creek is an approximately 29-mile-long (47 km) watercourse in Riverside County, in the U.S. state of California. Flowing primarily in a northwestern direction, it connects Lake Elsinore with the Santa Ana River. It drains the eastern slopes of the Santa Ana Mountains on its left and on its right the western slopes of the Temescal Mountains along its length. With a drainage basin of about 1,000 square miles (2,600 km2), it is the largest tributary of the Santa Ana River, hydrologically connecting the 720-square-mile (1,900 km2) San Jacinto River and Lake Elsinore watersheds to the rest of the Santa Ana watershed. However, flowing through an arid rain shadow zone of the Santa Ana Mountains, and with diversion of ground water for human use, the creek today is ephemeral for most of its length, except for runoff from housing developments and agricultural return flows.
Riverside County is a county located in the southern portion of the U.S. state of California. As of the 2020 census, the population was 2,418,185, making it the fourth-most populous county in California and the 10th-most populous in the United States. The name was derived from the city of Riverside, which is the county seat.
Temescal Mountains, also known as the Sierra Temescal, are one of the northernmost mountain ranges of the Peninsular Ranges in western Riverside County, in Southern California in the United States. They extend for approximately 25 mi (40 km) southeast of the Santa Ana River east of the Elsinore Fault Zone to the Temecula Basin and form the western edge of the Perris Block.
Temescal Valley in California is a graben rift valley in western Riverside County, California, a part of the Elsinore Trough. The Elsinore Trough is a graben between the Santa Ana Mountain Block to the southwest and the Perris Block on the northeast. It is a complex graben, divided lengthwise into several smaller sections by transverse faults. The Temescal Valley is one of these graben, at the northern end of the trough. The Temescal Valley graben is bounded northeast side by the Lee Lake longitudinal fault and similarly on the southeast by the Glen Ivy Fault.
Sedco Hills is the informal/local name for a southern section of the Temescal Mountains, located in southwestern Riverside County, California.
The Perris Block is the central block of three major fault-bounded blocks of the northern part of the Peninsular Ranges. The Perris Block lies between the Santa Ana Block to the west and the San Jacinto Block to the east. The Perris Block, was named by Walter A. English in 1925 for the city of Perris, located near the center of the block.
The Plains of Leon are named for the former gold mining town, Leon once located near the middle of the plain. It is a plain in the Perris Block, contiguous on the south with the Perris Plain including within it the Domenigoni Valley and western Diamond Valley, French Valley, Auld Valley, the upper part of the valley of Warm Springs Creek and connecting tablelands.
Warm Springs Valley is a valley located within the city of Lake Elsinore in Riverside County, California. It lies between the main body of the Temescal Mountains to the north, east and south and the Clevelin Hills to the west. The valley was named for the warm springs that used to be found flowing there.