Lets start your auto dealers license in California, City San Diego. San Diego is the eighth largest city in the largest city in the United States and second in California. The city is located in the Pacific off the coast of Southern California, which are directly the Mexican border. Birthplace of California, San Diego is known for year-round mild climate, its natural deep water port, and its long tradition of U.S. Navy. The population was 1,301,617 in 2010 census.