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.
Tongzi County is under the jurisdiction of Zunyi City, Guizhou Province. It is located in the north of Guizhou Province, bordering Chongqing in the north, Huichuan District and Renhuai City in the south, Xishui County and Qijiang District in Chongqing in the west, and Nanchuan District and Wansheng District in the north. The ground spans 27 °57 °N 28 °54 °N, 106 °26 °E and 107 °17 °E, with a total land area of 3202 square kilometers. Tongzi County has jurisdiction over 2 streets, 20 towns, 2 townships and 1 ethnic township. At the end of 2017, the registered population of Tongzi County was 742300. Tongzi County is "the hometown of bamboo shoots in China", known as "the gateway to northern Guizhou" and "the key to Sichuan and Guizhou". Sichuan-Guizhou Railway, National Highway 210 and Yu-Zhan Expressway run through the county, and the driving time from the county seat to Guiyang and Chongqing is about 2 hours. In September 2018, Tongzi County withdrew from the poverty-stricken county.