The Mazaruni River is a tributary of the Essequibo River in northern Guyana. Its source is in the remote western forests of the Pakaraima Mountains and its confluence with the Cuyuni River is near Bartica. As it descends from the Guiana Highlands the river runs south-east, past Issano, then northward to Bartica. The river is a source of alluvial gold.
The Mazaruni River takes source in the Roraima Plateau, three levels of sandstones and conglomerates, crowned by Mt. Roraima (2810 m.). In Guyana, the two highest levels of the Roraima Plateau are known as Pakaraima Mountains and Merume Mountains. The source of the Mazarunu River is in the Merume Mountains. The area is one of the very few places in the world still inaccessible. In 1992, a joint expedition of the Guyana Defence Force and Welsh Guards members was unable to reach the source of Mazaruni River, even with training, finances and equipment.
The Mazaruni River drops down from each Roraima plateau through three steep sided canyons with many picturesque sets of falls. The first set is Chai-chai Falls. The next is near village of Imbaimadai and the last set is below the village of Kamarang where the Mazaruni River tumbles through last few major falls, the first of which is a few kilometres long gutter known as Chitigokein Falls, which finishes in Coffy pool, a deep pool named after Mehir “Cousin Body” Coffy, one of the last "Porknockers" (these are small diamond and gold miners) of Guyana.The term "Porknockers" comes from the old prospectors having to carry in all their food one of which was salt pork which attracted flies and had to be knocked regularly to keep flies away. According to legend, during the 1950s, Coffy was diving in the river for diamonds when he got the bends, due to overstaying below and rapid decompression.
After few kilometres of relatively calm water, the last set of great Mazaruni River Falls begin. The first falls is the Aruwai Falls and the last is the Peaima Falls.