Arecibo (ah-re-SEE-boh) is a municipality in the northern midwest coast of Puerto Rico and located by the Atlantic Ocean, north of Utuado and Ciales; east of Hatillo; and west of Barceloneta, and Florida. Arecibo is spread over 18 wards and Arecibo Pueblo (The downtown area and the administrative center of the city). Arecibo is located on the north coast of the island of Puerto Rico, about 80 kilometres (50 miles) west of San Juan, or approximately a 1-hour trip by car. It is the largest city in area in Puerto Rico.

The nearby Arecibo Observatory is known for housing the world's largest radio telescope.