Guaynabo (Spanish pronunciation: [ɡwaiˈnaβo]) is a municipality in the northern part of Puerto Rico (US), located in the northern coast of the island, north of Aguas Buenas, south of Cataño, east of Bayamón, and west of San Juan. Guaynabo is spread over 9 wards and Guaynabo Pueblo (the downtown area and the administrative center of the suburb).
Guaynabo is considered, along with its neighbors – San Juan and the municipalities of Bayamón, Carolina, Cataño, Trujillo Alto, and Toa Baja – to be part of the San Juan metropolitan area. It is also part of the larger San Juan-Caguas-Guaynabo Metropolitan Statistical Area, (the largest MSA in Puerto Rico).
The municipality has a land area of 27.13 square miles (70.3 km2) and a population of 97,924 as of the 2010 census.
The first European settlement in Puerto Rico, Caparra, was founded in 1508 by Juan Ponce de León in land that is today part of Guaynabo. Ponce de León resided there as first Spanish governor of Puerto Rico. This settlement was abandoned in 1521 in favor of San Juan. The ruins of Caparra remain and are a U.S. National Historic Landmark. The Museum of the Conquest and Colonization of Puerto Rico, which features artifacts from the site and others in Puerto Rico, is located on the grounds.