Alajuela's 2026 population is now estimated at 444,371. In 1950, the population of Alajuela was 13,944. Alajuela has grown by 9,097 in the last year, which represents a 2.09% 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 Alajuela, which typically includes Alajuela's population in addition to adjacent suburban areas.