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.
Longchuan County, under the jurisdiction of Heyuan City, Guangdong Province, is located in the northeast of Guangdong Province, the northeast of Heyuan City, the upper reaches of Dongjiang and Hanjiang River, Xunwu County and Dingnan County of Jiangxi Province to the north, Wuhua County and Xingning City of Meizhou City to the east, Dongyuan County to the south and Heping County to the west. Laolong Town is the county seat. The county is a subtropical monsoon climate, mild climate, Rain Water abundant, sunny. At the end of 2018, the county has a total area of 3081.31 square kilometers and has jurisdiction over 24 towns, 315 villages and 42 neighborhood committees, with a total population of 986600, a permanent population of 713200 and 341000 overseas Chinese. Longchuan County has a long history and there were human activities as early as the Neolithic Age. Longchuan County was founded in 214BC (33 year of Qin Shihuang), which is one of the most ancient counties in China. Old Zhilong