With 4,061 square miles (10,517 km²), Los Angeles County borders 70 miles of coast on the Pacific Ocean and encompasses numerous other natural landscapes including towering mountain ranges, deep valleys, forests, islands, lakes, rivers, and desert. More specifically, the county contains the following rivers: Los Angeles River, Rio Hondo, the San Gabriel River and the Santa Clara River. The primary mountain ranges are the Santa Monica Mountains and the San Gabriel Mountains. It also includes the westernmost part of the Mojave Desert, and San Clemente Island and Santa Catalina Island in the Pacific Ocean.

 

Most of the population of Los Angeles County is located on the southern and southwestern portion of the county. The major population centers are the Los Angeles Basin and the San Fernando and San Gabriel Valleys. Moderate populations are in the Santa Clarita, Crescenta and Antelope Valleys.

 

The area north of the Santa Clarita Valley (Northwest Los Angeles County, adjacent to Ventura and Kern counties) is mostly mountainous, rugged, well-timbered and filled with coniferous forests that receives plentiful snow in the winter, right to the point of blizzard conditions. This area is less populated. Mountains in this area include San Emigdio Mountains, the southernmost part of Tehachapi Mountains, and the Sierra Pelona Mountains.

 

Most of the highest peaks in the county are located in the San Gabriel Mountains, which are part of the Transverse Ranges. They include Mount San Antonio (10,064 ft) at the Los Angeles-San Bernardino county lines, Mount Baden-Powell (9,399 ft), Mount Burnham (8,997 ft), and the well-known Mount Wilson (5,710 ft) where the Mount Wilson Observatory is located. Several smaller, lower peaks are located in the northern, western, and southwestern Los Angeles County.

Major divisions of the county

• Greater Los Angeles Area
• East: Eastside, San Gabriel Valley, Pomona Valley
• West: Westside, Beach Cities
• South: South Bay, Palos Verdes Peninsula South Los Angeles, Gateway Cities
• North: San Fernando Valley, portions of the Antelope Valley and Santa Clarita Valley
• Central: Downtown Los Angeles, Mid-Wilshire

Largest cities

Other cities

Unincorporated communities in Los Angeles County

The following areas are unincorporated regions of the county which fall directly under the county government's jurisdiction. Many, but not all of them, are Census-designated places. With no city government, residents of these areas must petition the appropriate member of the Board of Supervisors when they have a grievance about the quality of local services.

Many of these communities have town councils which are advisory bodies for the supervisor in the community. Typically these town councils are elected from the residents in a given region and have a direct channel to the supervisor and his staff to communicate concerns. Currently, Acton, Agua Dulce, Altadena, Castaic, Hacienda Heights, Juniper Hills, La Crescenta-Montrose, Littlerock, Quartz Hill, Rowland Heights, Topanga, and Val Verde have active town councils, though they may not be called by that name.