Zanjan's 2025 population is now estimated at 509,683. In 1950, the population of Zanjan was 41,029. Zanjan has grown by 7,233 in the last year, which represents a 1.44% 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 Zanjan, which typically includes Zanjan's population in addition to adjacent suburban areas.