Hainan is the smallest and southernmost province of the People's Republic of China. It is an island province located in the South China Sea. Hainan is separated from Guangdong province by the Qiongzhou Strait. The capital city of Hainan is Haikou, which is situated on the northern coast of the island. The province had a population of 10,081,232 in 2020.

Haikou is the capital and most populous city of the Chinese province of Hainan. Haikou was originally a port city, serving as the port for Qiongshan. Haikou was developed as a port during the Sino-Japanese War following Japanese occupation; after the war, Haikou and Hainan remained under Nationalist control until Landing Operation on Hainan Island, when it fell to Communist rule. Today, more than half of the island's total trade still goes through its ports.