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San Diego is a significant city in California, located in San Diego County on the Pacific Ocean’s southern California coast, roughly 120 miles (190 kilometers) south of Los Angeles and next to the Mexican border.
San Diego is the eighth-largest city in the United States and the second-largest in California, with an estimated population of 1,394,928 as of July 1, 2015. It is included in the San Diego–Tijuana conurbation, the second biggest transborder agglomeration in the United States after Detroit–Windsor, with a population of 4,922,723 people. San Diego, California’s birthplace, is noted for its moderate year-round temperature, natural deep-water port, wide beaches, historical relationship with the US Navy, and recent rise as a healthcare and biotechnology research hub.
San Diego, historically the home of the Kumeyaay people, was the first European settlement on what is now the West Coast of the United States. Juan Rodrguez Cabrillo claimed the whole territory for Spain upon his arrival in San Diego Bay in 1542, laying the groundwork for the establishment of Alta California 200 years later. Founded in 1769, the Presidio and Mission San Diego de Alcalá became the first European colony in what is now California. In 1821, San Diego became a part of newly independent Mexico, which reconstituted two years later as the First Mexican Republic. It became a part of the United States in 1850, after the Mexican–American War and California’s admittance to the union.
The city is the county headquarters of San Diego County and the economic hub of the San Diego–Tijuana metropolitan area. Military and defense-related enterprises, tourism, international commerce, and manufacturing are the city’s primary economic engines. The presence of the University of California, San Diego (UCSD) and its associated UCSD Medical Center has aided in establishing the city as a biotechnology research hub.