San Diego County, California

San Diego County, California

San Diego County is a county located in the southwestern corner of the U.S. state of California. It is the southwesternmost county in the 48 contiguous United States. Its county seat and largest city is San Diego. The county's population was about 2,813,835 in the 2000 U.S. Census. According to the 2010 U.S. Census, San Diego County had a population of 3,095,313 people, making it the second-most-populous county in California, after Los Angeles County. Its population in 2009 was estimated at 3,208,466, making it the fifth most-populous county in the United States and giving it a population greater than 20 of the 50 U.S. states.

San Diego County has 70 miles (110 km) of coastline. It has a mild Mediterranean to semi-arid climate. Also in this county are 16 significant naval and military locations of the United States Navy, U.S. Marine Corps and the U.S. Coast Guard, including Naval Base San Diego, Marine Corps Base Camp Pendleton, Marine Corps Air Station Miramar, and Naval Air Station North Island.

San Diego County defines the metropolitan statistical area of San Diego-Carlsbad-San Marcos, and in its metropolitan capacity is also known as Greater San Diego. In addition, San Diego County is part of the San Diego–Tijuana metropolitan area, an area with above five million people and the largest bi-national metropolitan area shared between the United States and Mexico. Arising from an effort by the state government to identify regional economies, San Diego County and Imperial County are part of the Southern Border Region, one of nine such regions. As a regional economy, the Southern Border Region is the smallest but most economically diverse region in the state, though the two counties maintain weak relations and have little in common, aside from their border proximity.

San Diego County extends south all the way to the Mexican border, which is also the northern border of the State of Baja California and the northern municipal limits of Tijuana Municipality and Tecate Municipality. San Diego County is bordered by Orange County and Riverside County on its north, by Imperial County on its east, and the Pacific Ocean on its west and southwest.