San Diego (pronounce /ˌsændiˈeɪgoʊ/) is a coastal Southern California city located in the southwestern corner of the continental United States. In 2006, the city's population was estimated to be 1,256,951. It is the second largest city in California and the eighth largest city in the United States, by population. It is the county seat of San Diego County. and is the economic center of the San Diego–Carlsbad–San Marcos metropolitan area, the 17th-largest in the United States with a population of 2.9 million as of 2006, and the 21st-largest metropolitan area in the Americas when including Tijuana (See San Diego-Tijuana Metro.).