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.
Longshan County, which belongs to Xiangxi Tujia and Miao Autonomous Prefecture, is located in the northwest of Hunan, in the hinterland of Wuling Mountains, connecting Jing Chu and Ba Shu, which is called "the Confucius of Hunan, Hubei and Sichuan" in history. The terrain is high in the north and low in the south, steep in the east and gentle in the west, with towering mountains and undulating peaks, including Youshui, Lishui and its tributaries. The region belongs to the subtropical continental humid monsoon climate zone with four distinct seasons. In 2013, Longshan County has a total area of 3131 square kilometers and has jurisdiction over 34 townships (streets) and 462 villages (communities), with a total population of 590000. 16 ethnic minorities, such as Tujia and Miao, account for 71% of the total population. In 2015, Longshan County has jurisdiction over 5 townships, 12 towns and 4 streets. Longshan has Oolong Mountain Grand Canyon, Lotta Stone Forest, Taiping Mountain Forest Park and other natural scenery. Coal, quartz sand, purple sand pottery,