Guaynabo is a city and municipality on the northeastern coastal plain of Puerto Rico. Located west of the capital San Juan, east of Bayamón, south of Cataño and San Juan Bay, and north of Aguas Buenas, Guaynabo is spread over 9 barrios and the downtown area and administrative center of Guaynabo Pueblo. With a land area of 27.13 square miles and a population of 89,780 as of the 2020 census, it is part of the San Juan metropolitan area.