Changdao County simplified Chinese: 长岛县; traditional Chinese: 長島縣; pinyin: Chángdǎo Xiàn; lit. 'long island county') was a county in Yantai, a prefectural area of Shandong in the People's Republic of China. It consists of the Changshan Islands within the Bohai Strait, directly north of Penglai. They were known for their sandy beaches and picturesque limestone cliffs. The total land area was only 56 square kilometers (22 sq mi), but the coastline is 146 km (91 mi) long. In 2020, Changdao County was merged to Penglai county-level city and became Penglai District.