The Northern Karst Belt is a limestone karst landscape located in the northern part of Puerto Rico. A karst is a topographical zone formed by the dissolution of soluble porous rocks, such as limestone, with features such as mogotes, canyons, caves, sinkholes, streams and rivers, all of which are common on this region of the island. Some of the island's main rivers, including its longest, traverse the karst and form some of the most distinctive Puerto Rican geographical features such as the Camuy caverns. Many of these rivers feed into and are important in the formation of many marshy areas such as the Caño Tiburones wetlands.

Arecibo is a city and municipality on the northern coast of Puerto Rico, on the shores of the Atlantic Ocean, located north of Utuado and Ciales; east of Hatillo; and west of Barceloneta and Florida. It is about 50 miles (80 km) west of San Juan, the capital city. Arecibo is the largest municipality in Puerto Rico by area, and it is the core city of the Arecibo Metropolitan Statistical Area and part of the greater San Juan–Bayamón, PR Combined Statistical Area. It is spread over 18 barrios and Arecibo Pueblo. Its population in 2020 was 87,754.