Downtown San Diego is the city center of San Diego, California, the eighth largest city in the United States. In 2010, the Centre City area had a population of more than 28,000. Downtown San Diego serves as the cultural and financial center and central business district of San Diego, with more than 4,000 businesses and nine districts. The downtown area is the home of the San Diego Symphony and the San Diego Opera as well as multiple theaters and several museums. The San Diego Convention Center and Petco Park, home of the San Diego Padres, are also located downtown. Downtown San Diego houses the major local headquarters of the city, county, state, and federal governments.

San Diego is a city on the Pacific Ocean coast in Southern California located immediately adjacent to the Mexico–United States border. With a population of over 1.3 million residents, the city is the eighth-most populous in the United States and the second-most populous in the state of California after Los Angeles. The city is the seat of San Diego County, which has a population of nearly 3.3 million people as of 2021. San Diego is known for its mild year-round Mediterranean climate, extensive beaches and parks, its long association with the United States Navy, and its recent emergence as a healthcare and biotechnology development center.