Kisumu's 2025 population is now estimated at 422,148. In 1950, the population of Kisumu was 12,103. Kisumu has grown by 15,464 in the last year, which represents a 3.8% 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 Kisumu, which typically includes Kisumu's population in addition to adjacent suburban areas.