Los Angeles County, officially the County of Los Angeles, and sometimes abbreviated as L.A. County, is the most populous county in the United States, with 9,861,224 residents estimated in 2022. Its population is greater than that of 40 individual U.S. states. Comprising 88 incorporated cities and many unincorporated areas within a total area of 4,083 square miles (10,570 km2), it is home to more than a quarter of Californians and is one of the most ethnically diverse U.S. counties. The county's seat, Los Angeles, is the second most populous city in the United States, with 3,822,238 residents estimated in 2022.
The San Gabriel Mountains comprise a mountain range located in northern Los Angeles County and western San Bernardino County, California, United States. The mountain range is part of the Transverse Ranges and lies between the Los Angeles Basin and the Mojave Desert, with Interstate 5 to the west and Interstate 15 to the east. The range lies in, and is surrounded by, the Angeles and San Bernardino National Forests, with the San Andreas Fault as its northern border.
The San Gabriel Valley, often referred to by its initials as SGV, is one of the principal valleys of Southern California, lying immediately to the east of the eastern limits of the city of Los Angeles and occupying the vast majority of the southeastern part of Los Angeles County. Surrounding landforms and other features include the following:
Seven Oaks Dam is a 550-foot (170 m) high earth and rock fill embankment dam across the Santa Ana River in the San Bernardino Mountains, about 4 miles (6.4 km) northeast of Redlands in San Bernardino County, southern California. It impounds Seven Oaks Reservoir in the San Bernardino National Forest.
Pyramid Lake is a reservoir formed by Pyramid Dam on Piru Creek in the eastern San Emigdio Mountains, near Castaic, Southern California. It is a part of the West Branch California Aqueduct, which is a part of the California State Water Project. Its water is fed by the system after being pumped up from the San Joaquin Valley and through the Tehachapi Mountains.
Naval Air Weapons Station (NAWS) China Lake is a large military installation in California that supports the research, testing and evaluation programs of the United States Navy. It is part of Navy Region Southwest under Commander, Navy Installations Command, and was originally known as Naval Ordnance Test Station (NOTS).
The San Gabriel River is a mostly urban waterway flowing 58 miles (93 km) southward through Los Angeles and Orange Counties, California in the United States. It is the central of three major rivers draining the Greater Los Angeles Area, the others being the Los Angeles River and Santa Ana River. The river's watershed stretches from the rugged San Gabriel Mountains to the heavily developed San Gabriel Valley and a significant part of the Los Angeles coastal plain, emptying into the Pacific Ocean between the cities of Long Beach and Seal Beach.
After 1900, California continued to grow rapidly and soon became an agricultural and industrial power. The economy was widely based on specialty agriculture, oil, tourism, shipping, film, and after 1940 advanced technology such as aerospace and electronics industries – along with a significant military presence. The films and stars of Hollywood helped make the state the "center" of worldwide attention. California became an American cultural phenomenon; the idea of the "California Dream" as a portion of the larger American Dream of finding a better life drew 35 million new residents from the start to the end of the 20th century (1900–2010). Silicon Valley became the world's center for computer innovation.
The California State Water Project, commonly known as the SWP, is a state water management project in the U.S. state of California under the supervision of the California Department of Water Resources. The SWP is one of the largest public water and power utilities in the world, providing drinking water for more than 27 million people and generating an average of 6,500 GWh of hydroelectricity annually. However, as it is the largest single consumer of power in the state itself, it has a net usage of 5,100 GWh.
Tujunga Wash is a 13-mile-long (20.9 km) stream in Los Angeles County, California. It is a tributary of the Los Angeles River, providing about a fifth of its flow, and drains about 225 square miles (580 km2). It is called a wash because it is usually dry, especially the lower reaches, only carrying significant flows during and after storms, which usually only occur between November and April. The name of the wash derives from a Tongva village name.
Bouquet Reservoir is an artificial lake in the Angeles National Forest of Los Angeles County, California about 15 miles (24 km) west from Palmdale.
The Los Angeles flood of 1938 was one of the largest floods in the history of Los Angeles, Orange, and Riverside Counties in southern California. The flood was caused by two Pacific storms that swept across the Los Angeles Basin in February-March 1938 and generated almost one year's worth of precipitation in just a few days. Between 113–115 people were killed by the flooding. The Los Angeles, San Gabriel, and Santa Ana Rivers burst their banks, inundating much of the coastal plain, the San Fernando and San Gabriel Valleys, and the Inland Empire. Flood control structures spared parts of Los Angeles County from destruction, while Orange and Riverside Counties experienced more damage.
Puddingstone Reservoir is a 250-acre (1 km²) artificial lake northeast of the interchange between the Orange Freeway and the San Bernardino Freeway in Los Angeles County, California, United States. Activities include fishing, swimming, sailing, windsurfing, and camping. It is fed by Live Oak Wash and drains into Walnut Creek.
The Sierra Madre Dam is a dam on Little Santa Anita Creek, at the mouth of Little Santa Anita Canyon, in Los Angeles County, California. It is in the San Gabriel Mountains, south of the Angeles National Forest, on the northern border of Sierra Madre.
Santa Fe Dam is a flood-control dam on the San Gabriel River located in Irwindale in Los Angeles County, California, United States. For most of the year, the 92-foot (28 m)-high dam and its reservoir lie empty, but can hold more than 45,000 acre-feet (56,000,000 m3) of water during major storms. During the dry season, the basin behind the dam is used for groundwater recharge, as well as various recreational activities.
San Gabriel Dam is a rock-fill dam on the San Gabriel River in Los Angeles County, California, within the Angeles National Forest. Completed in 1939, the dam impounds the main stem of the San Gabriel River about 2.5 miles (4.0 km) downstream from the confluence of the river's East and West Forks, which drain a large portion of the San Gabriel Mountains. It is located directly upstream from the Morris Dam. The dam provides flood control, groundwater recharge flows and hydroelectricity for the heavily populated San Gabriel Valley in the Greater Los Angeles metropolitan area.
Morris Dam is a concrete gravity dam across the San Gabriel River in the U.S. state of California. It impounds Morris Reservoir, directly downstream of San Gabriel Dam.
Cogswell Dam is a rockfill dam on the West Fork of the San Gabriel River in Los Angeles County, California. It is located in the San Gabriel Mountains, northeast of Mount Wilson, and within the Angeles National Forest.
San Dimas Dam is a concrete gravity dam in Los Angeles County, California. The dam and its flood control basin/reservoir are in the San Gabriel Mountains and within the Angeles National Forest. The dam is currently operated by the Los Angeles County Department of Public Works but was originally built by the Los Angeles County Flood Control District in 1922. The dam controls flooding from San Dimas Creek, a major San Gabriel Mountains drainage and tributary of the San Gabriel River. As a flood control facility the San Dimas Reservoir is dry for most of the year, only storing water after significant winter storms. The regulation provided by the dam allows for the efficient diversion of floodwaters from San Dimas Wash to Puddingstone Reservoir, which protects the San Dimas area of the San Gabriel Valley.
The San Gabriel Complex Fire was a wildfire that burned in 2016 in the Angeles National Forest, Los Angeles County, California, United States. It was the combination of two separate wildfires: the Reservoir Fire and the Fish Fire, both of which ignited on June 20.
