Southern California is a geographic and cultural region that generally comprises the southern portion of the U.S. state of California. It includes the Los Angeles metropolitan area, the second most populous urban agglomeration in the United States. The region generally contains ten of California's 58 counties: Imperial, Kern, Los Angeles, Orange, Riverside, San Bernardino, San Diego, Santa Barbara, San Luis Obispo and Ventura counties. The Colorado Desert and the Colorado River are located on southern California's eastern border with Arizona, and San Bernardino County shares a border with Nevada to the northeast. Southern California's southern border with Baja California is part of the Mexico–United States border. Over time, droughts and wildfires have increased in frequency and become less seasonal and more year-round, further straining the region's water security.
Tijuana is a city in Baja California, Mexico. It is part of the San Diego–Tijuana transborder urban agglomeration and the larger Southern California megalopolis. As the second-largest city in Mexico and center of the 6th-largest metro area in Mexico, Tijuana exerts a strong influence in education and politics, in transportation, culture, art, and manufacturing and as a migration hub. Currently one of the fastest-growing metropolitan areas in Mexico, Tijuana is rated as a "High Sufficiency" global city by the Globalization and World Cities Research Network. As of September 2019, the city of Tijuana had a population of 1,810,645, with its metropolitan area containing a population of 2,157,853 as of 2020, an estimated 2,002,000 within the urban area.
Imperial Beach is a residential beach city in San Diego County, California, with a population of 26,324 at the 2010 census. The city is the southernmost city in California and the West Coast of the United States. It is in the South Bay area of San Diego County, 14.1 miles (22.7 km) south of downtown San Diego and 5 miles (8 km) northwest of downtown Tijuana, Mexico.
Rosarito is a coastal resort city in the Mexican state of Baja California located approximately 10 miles (16 km) south of the U.S. border in Rosarito Beach Municipality. Often mistakenly called Rosarito Beach because of the well-known Rosarito Beach Hotel, the town of Rosarito is one part of the municipality named Playas de Rosarito.
The Tijuana River is an intermittent river, 120 mi (195 km) long, near the Pacific coast of northern Baja California state in northwestern Mexico and Southern California in the western United States. The river is heavily polluted with raw sewage from the city of Tijuana, Mexico.
Ballona Wetlands State Ecological Reserve is located in Los Angeles County, California, just south of Marina del Rey and east of Playa del Rey. The natural wetlands once included the areas now taken up by Marina del Rey, New Amsterdam Canals of Venice, Playa Vista, northern Playa del Rey, and formerly extended northerly beyond Venice Boulevard to the historical Venice Canals that are now covered in asphalt with 6 streets.
South Bay, also known as South County, is a region in southwestern San Diego County, California consisting of the cities and unincorporated communities of Bonita, Chula Vista, Imperial Beach, Lincoln Acres, National City, and South San Diego.
San Diego–Tijuana is an international transborder agglomeration, straddling the border of the adjacent North American coastal cities of San Diego, California, United States and Tijuana, Baja California, Mexico. The 2012 population of the region was 4,922,723, making it the largest bi-national conurbation shared between the United States and Mexico, the second-largest shared between the US and another country. In its entirety, the region consists of San Diego County in the United States and the municipalities of Tijuana, Rosarito Beach, and Tecate in Mexico. It is the third most populous region in the California–Baja California region, smaller only than the metropolitan areas of Greater Los Angeles and the San Francisco Bay Area.
Playas de Tijuana is the westernmost borough of the municipality of Tijuana, Baja California, stretching from the United States border in the north to Rosarito Beach Municipality in the south. The Bullring by the Sea was opened in 1960.
Tijuana Slough National Wildlife Refuge is located in the most southwestern corner of the contiguous United States. As a National Wildlife Refuge, it is administered by the U.S. Fish and Wildlife Service. It was established in 1980.
Tijuana River National Estuarine Research Reserve is a natural reserve in Imperial Beach, California and San Ysidro, San Diego. It encompasses the Tijuana River Estuary, located on the Mexico–United States border. It is divided into two parts: the Tijuana Slough National Wildlife Refuge on the north, and Border Field State Park in the south.
San Diego County, officially the County of San Diego, is a county in the southwestern corner of the state of California, in the United States. As of the 2020 census, the population was 3,298,634, making it California's second-most populous county and the fifth-most populous in the United States. Its county seat is San Diego, the second-most populous city in California and the eighth-most populous city in the United States. It is the southwesternmost county in the 48 contiguous United States, and is a border county.
The Tijuana River Valley is a rural community in the southern section of San Diego, California. It neighbors Imperial Beach to the north and west, Egger Highlands and Nestor to the north, San Ysidro to the east, and the U.S.-Mexico border to the south. Major thoroughfares include Hollister Street, Monument Road, and Dairy Mart Road.
The Tijuana River Estuary is an intertidal coastal wetland at the mouth of the Tijuana River in San Diego County, California, in the United States bordering Tijuana, Baja California, Mexico. It is the location of the Tijuana River National Estuarine Research Reserve, Tijuana Slough National Wildlife Refuge, and Border Field State Park. The estuary is a shallow water habitat. Often termed an intermittent estuary since its volume is subject to the discharge controlled by the seasons of the year, the volume of the estuary fluctuates and at times there is dry land, or flooded areas. It was designated a National Natural Landmark in 1973.
Friendship Park is a half-acre binational park located along the United States-Mexico border in the San Diego–Tijuana region. Located within the larger Border Field State Park in California's San Diego county, the park includes the border fence dividing the two countries where residents of both countries can meet in person. On the U.S. side, the park used to be part of the Monument Mesa picnic area but is now wholly located on federal property under the Department of Homeland Security and is heavily monitored by U.S. Border Patrols 24 hours a day. To the south of this place is the Playas de Tijuana, Baja California.
Tijuana River Mouth State Marine Conservation Area (SMCA) is a marine protected area that extends offshore of southern San Diego County on California’s south coast. The SMCA covers 2.91 square miles.
The Initial Point of Boundary Between U.S. and Mexico is the westernmost boundary marker on the international boundary between the United States and Mexico and as such has since its erection and will throughout the future mark the southwestern corner of the Continental United States. According to the 1848 Treaty of Guadalupe Hidalgo, the initial border point is set as one marine league south of the southernmost point of San Diego Bay, and the border proceeds in a straight line towards the confluence of the Colorado River and Gila River.
Goat Canyon also known as Cañón de los Laureles, begins in Tijuana, Mexico, and ends in the United States just north of the Mexico–U.S. border. The canyon is formed by Goat Canyon Creek, which receives water and other runoff from areas south of the border. Most of the canyon and its watershed lies within Baja California.
The Smuggler's Gulch is part of a steep walled canyon about 2 miles (3.2 km) inland of the Pacific Ocean. The canyon crosses the Mexico–United States border, between Tijuana, Baja California, and San Diego, California, and Smuggler's Gulch is the part of the canyon on the US side of the border. It may also be called Cañón del Matadero or Valle Montezuma in Spanish, but these names apply more generally to the whole canyon. Smuggling activities within Smuggler's Gulch have occurred since the 19th century, giving this part of the canyon its name.
