Changhai County, belongs to Dalian City, Liaoning Province. It is the only island county in Northeast China and the only island border county in China. It is located on the east side of Liaodong Peninsula, in the northern waters of the Yellow Sea, between longitude 122°13′18″-123°17′38″E and latitude 38°55′48″-39°18°26″N. The county is located in the eastern part of the Liaodong Peninsula, in the northern waters of the Yellow Sea. East and the Korean Peninsula, southwest of Shandong Province, opposite the Temple Island Archipelago, west and north of the sea adjacent to the city of Dalian and Pulandian City, Zhuanghe City, with a total area of 154 square kilometers. As of June 2023, Changhai County has five towns under its jurisdiction.In 2021, Changhai County had a household population of 68,300 people. In November, 1945, Changshan District was established in Xinjin County (now Pulandian District), and Shicheng Island District was established in Zhuanghe County. In 1947, Changshan District, Guanglu District, Ocean Island and Wuyong Island were merged into Changshan Island, which was renamed Jin County. 1949, Changshan Island District was changed into a county, and in 1953, Changshan County was renamed Changhai County. In 2022, the gross regional product of Changhai County was 10.11 billion yuan, an increase of 3.8%. By industry, the added value of primary industry is 6.55 billion yuan, the added value of secondary industry is 140 million yuan; the added value of tertiary industry is 3.41 billion yuan, an increase of 5.2%.