Cayo is a district in the west of the nation of Belize. The District capital is the town of San Ignacio.
The Cayo District is the largest district in Belize. Within the Cayo District are the national capital of Belmopan, the district capital of San Ignacio, the town of Benque Viejo del Carmen, and the villages of San Antonio Cayo, Valley of Peace, St. Margaret's, Roaring Creek, Armenia, San Jose Succotz, Arenal, Buena Vista, Calla Creek, Esperanza, Cristo Rey, Georgeville, Unitedville, Blackman Eddy, Ontario, Camalote, Los Tambos, More Tomorrow and Spanish Lookout.
Cayo District also contains the Pre-Columbian Maya ruins of Xunantunich, Cahal Pech, Chaa Creek, and Caracol. Major rivers in the Cayo District include the Macal River and the Mopan River.
The Cayo District is primarily an agricultural district, with the chief crops being citrus, (oranges, grapefruit, and tangerine), as well as bananas. Recently oil was found in Spanish Lookout and is now in production.
There are 2 major highways in the District. The Western Highway runs from Belize City to the Guatemalan border, and the Hummingbird Highway which starts in Belmopan and ends at the juncture of the Coastal Road and the Southern Highway in the Stann Creek District.
In addition to the ruins listed above there are several other important nature reserves including two National Parks, Blue Hole (park) and Guanacaste National Park. Ecotourism is also an integral part of the region's economy.
According to the 2000 census, Cayo District had a population of 53,715 people.