Juncos is a town and one of the 78 municipalities of Puerto Rico. It is located in the eastern central region of the island to the west of the Caguas Valley, south of Canóvanas and Carolina; southeast of Gurabo; east of San Lorenzo; and west of Las Piedras. Juncos is spread over 9 barrios and Juncos barrio-pueblo. It is part of the San Juan-Caguas-Guaynabo Metropolitan Statistical Area.

Carolina is a city and municipality located on the northeast coast of Puerto Rico. It lies immediately east of the capital San Juan and Trujillo Alto; north of Gurabo and Juncos; and west of Canóvanas and Loíza. Carolina is spread over 12 barrios plus Carolina Pueblo. It is part of the San Juan-Caguas-Guaynabo Metropolitan Statistical Area, and home to Puerto Rico's main airport, the Luis Muñoz Marín International Airport.