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.
Rongjiang, formerly known as Guzhou, is one of the 800 prefectures in the south of the Yangtze River, belonging to Qiandongnan Miao and Dong Autonomous Prefecture. It is located between 108 °04 east longitude and 108 °44 'east longitude and 25 °26 °28' north latitude. It is located in the center of the junction of Hunan, Guizhou and Guangxi provinces, bordering Liping County and Congjiang County in the east, Leishan County and Sandu County in the west, Jianhe County in the north and Libo County in the south. It has been known as "the lock key in southeastern Guizhou Province and the first important area in Miaojiang" since ancient times. The county has a total area of 3315.8 square kilometers and has jurisdiction over 6 towns, 13 townships and 268 administrative villages, with a total population of 350000, of which 298000 are from Dong, Miao, Shui, Yao and other ethnic minorities, accounting for 85.14% of the total population. The government is stationed in Guzhou town. With a mild climate and abundant rainfall, Rongjiang is the "priority tourism development area of Guizhou Province".