The population of The Gambia (2001 estimate) is 1,411,205, making it one of the least populous countries of Africa. Still, the country has an overall population density of 125 persons per sq km (324 per sq mi), and the population is increasing at a rate of 3.1 percent a year. Banjul, formerly called Bathurst, is the capital and only seaport. The largest city is Serrekunda.

The river basin was a focal point for migrating groups of people escaping the turmoil of western Sudanic wars dating from the 12th century. The Diola (Jola) are the people longest resident in the country; they are now located mostly in western Gambia. The largest group is the Malinke (Mandingo), comprising about two-fifths of the population. The Wolof are the largest population group in Banjul. Nomadic Fulani (Fula) settled the extreme upriver areas, and their kingdom, Fuladu, became a major power. The Soninke (Serahuli), an admixture of Malinke and Fulani, are also concentrated in the upriver areas. The population is more than 90 percent Muslim.