Arrah's 2025 population is now estimated at 369,680. In 1950, the population of Arrah was 63,400. Arrah has grown by 8,390 in the last year, which represents a 2.32% 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 Arrah, which typically includes Arrah's population in addition to adjacent suburban areas.