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.
Xinlong County, which belongs to Ganzi Tibetan Autonomous Prefecture of Sichuan Province, is located in the middle of Ganzi Prefecture in Sichuan Province and the southeast edge of Qinghai-Tibet Plateau. It belongs to the contact zone between West Sichuan Mountain Plain and Hengduan Mountains. Xinlong County is connected with Luhuo County and Daofu County to the east, Yajiang County and Litang County to the south, Baiyu County to the west, Ganzi County to the north, Dege County to the northwest, and latitude 30 °23 to 31 °32 'and longitude 99 °37 to 100 °54' east. The terrain of Xinlong County is high in the north and low in the south. The highest elevation is 5992 meters and the lowest point is 2760 meters above sea level. Ganzi Xinlong Highway to the north of Xinlong County is connected with National Highway 317 via 100 kilometers. By the end of 2013, Xinlong County has an area of 9182.74 square kilometers and has jurisdiction over 1 town, 18 townships and 1 street office, with a total population of 49833. 2013