The following outline is provided as an overview of and topical guide to San Diego:
San Diego (/ˌsæn diˈeɪɡoʊ/ SAN dee-AY-goh, Spanish: [san ˈdjeɣo]) is a city on the Pacific coast of Southern California, immediately adjacent to the Mexico–United States border. With a population of over 1.3 million residents, it is the eighth-most populous city in the United States and the second-most populous in the state of California, after Los Angeles. San Diego is the seat of San Diego County, which has a population of nearly 3.3 million people. It is known for its mild year-round Mediterranean climate, extensive beaches and parks, long association with the United States Navy, and recent emergence as a healthcare and biotechnology development center.