The Gambia River is one of the smallest rivers in Africa, running just 1,130 km (700 miles) from the Fouta Djallon plateau in north Guinea to the Atlantic Ocean at the capital city, Banjul. It is navigable for about half that length.

The river is known largely because of Gambia, the smallest country in Africa, which consists of little more than half the river and its two banks.

According to Alex Haley's novel Roots, the Gambia River provided one of the clues that helped him trace his American family history back to Africa. The words "Kamby Bolongo" were among the few words that his family had been passed down from generation to generation; he discovered that a bolongo was a "moving water" or "river" in the Mandinka language, so he concluded that the phrase probably refered to the Gambia River. His theory was confirmed when he traveled to Juffure, The Gambia, on the north bank of the river, and found that their oral family histories complemented his.