MacCarthy Island, island, in the Gambia River, 176 miles (283 km) upstream from Banjul, central Gambia. It was ceded in 1823 to Captain Alexander Grant of the African Corps, who was acting for the British crown. Designated as a site for freed slaves, the island was renamed for Sir Charles MacCarthy, British colonial governor (1814–24). In the 1830s peanut (groundnut) cultivation was introduced by the Wesleyan Mission at the port town of Georgetown (q.v.) on the island. The island is 6 miles (10 km) long and 1.5 miles (2.5 km) wide and is chiefly inhabited by Malinke (Mandingo) people. Pop. (latest census) 2,510.