Cagayancillo is a sixth class island municipality in the province of Palawan, Philippines, located between the islands of Palawan and Negros in the Sulu Sea. As of the 2010 census, it has a population of 7,116 people. Cagayancillo is the closest settlement to the Tubbataha National Marine Park. The word Cagayancillo is Spanish for "Little Cagayan."
The farthest provincial limit of the province of Palawan in the east is the island of municipality of Cagayancillo. It is approximately 178 nautical miles (330 km) east of Puerto Princesa City and only 72 nautical miles (133 km) south-west of Antique. It is located near the middle of the Sulu Sea.
There are neither mountain ranges nor forested areas in the municipality. A hilly portion in the north-eastern part of the main island has a slope of 3-82%. The other areas are flat with the highest elevation around 2 to 3 meters. The majority of the island has a sandy loam soil not enough to support a forest.
Cagayancillo is the smallest municipality in the province of Palawan with a total land area of only 2,639 hectares (6,520 acres) as of 2007. The municipality is composed of 31 islands and islets and is subdivided into 12 barangays and two island sitios (Cavili and Calusa) included under the political jurisdiction of Magsaysay.