San Diego (/ˌsæn diˈeɪɡoʊ/ SAN dee-AY-goh, Spanish: [san ˈdjeɣo]; Spanish for 'Saint Didacus') is a city on the Pacific Ocean coast of Southern California located immediately adjacent to the Mexico–United States border. With a 2020 population of 1,386,932, it is the eighth most populous city in the United States and the seat of San Diego County, the fifth most populous county in the United States, with 3,338,330 estimated residents as of 2019. The city is known for its mild year-round climate, natural deep-water harbor, extensive beaches and parks, long association with the United States Navy, and recent emergence as a healthcare and biotechnology development center. San Diego is the second largest city in the state of California, after Los Angeles.
Tongchuan District, which belongs to Dazhou City, Sichuan Province, is located in the northeast of Sichuan Province and in the middle of Dazhou City, adjacent to Xuanhan County in the northeast, Dachuan District in the southwest and Pingchang County in the northwest. As of October 2018, Tongchuan District has jurisdiction over 19 townships and 3 subdistrict offices, covering an area of 900square kilometers and a resident population of 782100. It is a national advanced area of scientific and technological progress, a national demonstration area of harmonious community construction, a national demonstration base of agricultural products processing industry, an advanced area of safe construction, an advanced area of hilly areas, and a demonstration area of rural tourism. Tongchuan District, which was established in 1999 as the seat of the state and government, is the political, economic and cultural center of Dazhou City. The four leading groups of the Municipal Party Committee, the Municipal Government, the Municipal people's Congress, the Municipal people's political Consultative Conference and the major administrative departments are all located in Tongchuan, which is known as "the heart of Dazhou".