Changdao County, because of the territory of Changshan Island and named, the original county under the jurisdiction of Yantai City, Shandong Province. Changdao County is located between Jiaodong and Liaodong Peninsula, at the junction of the Yellow Sea and the Bohai Sea. It is located in the connecting belt of the Bohai economic Circle. It is the only island county in Shandong Province. Changdao County consists of 32 islands, of which 10 are inhabited. The land area of the island is 56.8 square kilometers, the sea area is 3541 square kilometers, and the coastline is 187.8 kilometers.

The main tourist attractions in Changdao County include Jiuzhang Cliff, Half Moon Bay National Geopark, Miaodao Ancient Temple Group, Fairyland Source Folk Customs Park, Linhaifeng Mountain National Forest Park, Miaodao Mazu Cultural Park, Beizhuang Ruins and so on.

In June 2018, the People's Government of Shandong Province officially approved the establishment of the Changdao Marine Ecological Civilization Comprehensive Pilot Zone. In November 2018, Changdao County was selected into the 2018 National "100 Happy Counties" list. The third batch of practice and innovation bases "lucid waters and lush mountains are invaluable assets".

In June 2020, The State Council approved the abolition of Penglai City and Changdao County and the establishment of Penglai District, taking the former administrative areas of Penglai City and Changdao County as the administrative areas of Penglai District; On September 1, 2006, Penglai District was officially established, and Changdao operated independently according to the provincial functional zone system for Marine ecological civilization construction.