Haikou, also spelled as Hoikow is the capital and most populous city of the Chinese province of Hainan. Haikou city is situated on the northern coast of Hainan, by the mouth of the Nandu River. The northern part of the city is the district of Haidian Island, which is separated from the main part of Haikou by the Haidian River, a branch of the Nandu. Administratively, Haikou is a prefecture-level city, comprising four districts, and covering 2,280 square kilometres. There are 2,046,189 inhabitants in the built up area all living within the 4 urban districts of the city.
Haikou was originally a port city, serving as the port for Qiongshan. Haikou and Hainan remained under Nationalist control until Landing Operation on Hainan Island, when it fell to Communist rule. Currently, more than half of the island's total trade still goes through its ports. The Temple of the Five Lords is located to the southeast of the city.
The city is home to Hainan University, a comprehensive research university under the Project 211 and the Double First Class University Plan in certain disciplines, which has its main campus on Haidian Island.