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.
Baiyu County, which belongs to Ganzi Tibetan Autonomous Prefecture of Sichuan Province, is located in the transitional zone from Qinghai-Tibet Plateau to Yunnan-Guizhou Plateau. It belongs to the northern section of the Hengduan Mountains and the east bank of the upper reaches of the Jinsha River. It is located between 98 degrees 36 minutes east longitude to 99 degrees 56 minutes and 30 degrees 22 minutes to 31 degrees 40 minutes north latitude. It is bordered by Xinlong County to the east, Batang and Litang counties to the south, Gongjue and Jiangda counties in Tibet to the west, and Ganzi County and Dege County to the north. By the end of 2011, Baiyu County had an area of 10591 square kilometers and had jurisdiction over 1 town and 16 townships with a total population of 53600, a birth rate of 8.64 ‰ and a natural population growth rate of 6.67 ‰. In 2011, Baiyu County achieved a GDP of 869 million yuan, an increase of 9.7% over 2010.