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.
Yiyuan County, which belongs to Zibo City, Shandong Province, is located in the middle of Shandong Province, Linqu County of Weifang City to the east, Yishui County to the southeast, Laiwu District and Gangcheng District of Jinan City to the west, Xintai City of Taian City to the southwest, Mengyin County of Linyi City to the south, and Boshan District and Zichuan District to the north. In 1944, it established a county with a total area of 1636 square kilometers, with 10 towns, 2 streets, 1 provincial economic development zone and 643 villages (communities) under its jurisdiction by 2017. As of December 31, 2017, the total population of Yiyuan County is 569900. Yiyuan is the roof of Shandong Province, China, with an average elevation of 401 meters, which is the highest in Shandong Province. There are 1983 famous hills in the territory, and the highest elevation of Mount Lushan is 1108 meters, which is the fourth peak in Shandong Province. There are 1530 large and small rivers.