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.
Yangshan County, which belongs to Qingyuan City, Guangdong Province, is located in the northwest of Guangdong Province, the middle part of Qingyuan, the southern foot of Nanling Mountains and the middle reaches of Lianjiang River. it is located between longitude 112 °22 °01mm east and latitude 23 °58470 °24 °5552' north. It is one of the 21 key counties of poverty alleviation and development in Guangdong Province. There was Yangyu State in the warring States period, Yangshanguan was established at the end of the Qin Dynasty, and Yangshan County was located in Gaozu of the Western Han Dynasty, which has a history of more than 2200 years. The county has a total area of 3418 square kilometers and has jurisdiction over 12 towns and one Yao township. As of 2018, Yangshan County has a total population of 569000. Yangshan County, 160 kilometers away from Guangzhou, is an important part of the "two-hour life circle" in the Pearl River Delta. The waterway is convenient. Lianjiang flows through the county from north to south, all the year round.