Haimen's 2021 population is now estimated at 645,598. In 1950, the population of Haimen was 3,118. Haimen has grown by 19,531 since 2015, which represents a 3.12% annual change. These population estimates and projections come from the latest revision of the UN World Urbanization Prospects. These estimates represent the Urban agglomeration of Haimen, which typically includes Haimen's population in addition to adjacent suburban areas.