Mao, city, northwestern Dominican Republic. It lies near the Yaque del Norte River in the fertile Cibao Valley. Mao is principally a rice-growing and milling centre, although a variety of other crops are grown in the area. Lumbering and placer gold mining take place near the city. Mao can be reached by secondary highways linking Santo Domingo with Monte Cristi in the extreme northwest. Pop. (2002) urban area, 47,828; (2010) urban area, 49,243.