Seongnam's 2021 population is now estimated at 942,342. In 1950, the population of Seongnam was 54,507. Seongnam has grown by -1,426 since 2015, which represents a -0.15% 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 Seongnam, which typically includes Seongnam's population in addition to adjacent suburban areas.