San Diego County is a county located in the southwestern corner of the U.S. state of California. It is the most southwestern county in the 48 contiguous United States. Its county seat and largest city is San Diego. 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- first being Los Angeles County. San Diego County has 70 miles of coastline. It has a mild Mediterranean to semi-arid climate. There is also 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 as Greater San Diego. San Diego County is also part of the San Diego–Tijuana metropolitan area. This area, having about five million people, is the largest 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. However, the two counties maintain weak relations and have little in common aside from their border proximity. Wikipedia [ - ]

San Diego County is a county located in the southwestern corner of the U.S. state of California... [ + ]