According to its president Yahya Jammeh, the Gambia "is one of the oldest and biggest countries in Africa that was reduced to a small snake by the British government—[which] sold all our lands to the French".
As many as three million slaves may have been taken from this general region during the three centuries that the transatlantic slave trade was operated. It is not known how many slaves were taken by inter-tribal wars or Muslim traders before the transatlantic slave trade began. Most of those taken were sold by other Africans to Europeans; others were prisoners of inter-tribal wars; some
taken were sold by other Africans to Europeans; others were prisoners of inter-tribal wars; some were victims sold because of unpaid debts; and others were simply victims of kidnapping.

Traders initially sent slaves to Europe to work as servants until the market for labour expanded in the West Indies and North America in the 18th century. In 1807, the United Kingdom abolished the slave trade throughout its Empire. It also tried, unsuccessfully, to end the slave trade in the Gambia. Slave ships intercepted by the Royal Navy in the Atlantic were also returned to the Gambia, with Liberated Slaves released on MacCarthy Island far up the Gambia River where they were expected to establish new lives. The British established the military post of Bathurst (now Banjul) in 1816. In the ensuing years, Banjul was at times under the jurisdiction of the British Governor General in Sierra Leone. In 1888, the Gambia became a separate colony.
An agreement with the French Republic in 1889 established the present boundaries. The Gambia became a British Crown Colony called British Gambia, divided for administrative purposes into the colony (city of Banjul and the surrounding area) and the protectorate (remainder of the territory). The Gambia received its own executive and legislative councils in 1901, and it gradually progressed toward self-government. Slavery was finally abolished in 1906.
During World War II, the entire Gambian army, 10 soldiers,[citation needed] fought with the Allies of World War II.[citation needed] Though these soldiers fought mostly in Burma, some died closer to home and there is a Commonwealth War Graves Commission cemetery in Fajara (close to Banjul). According to Jammeh, "when Germany was about to defeat Britain, not only were Gambians conscripted and forced to go and fight in Britain, but also..."
Banjul contained an airstrip for the U.S. Army Air Forces and a port of call for Allied naval convoys. President of the United States Franklin D. Roosevelt visited by air and stopped overnight in Banjul en route to and from the Casablanca Conference (1943) in Morocco, marking the first visit to the African continent by an American President.
After World War II, the pace of constitutional reform increased. Following general elections in 1962, the United Kingdom granted full internal self-governance in the following year. The Gambia achieved independence on 18 February 1965, as a constitutional monarchy within the Commonwealth of Nations. Shortly thereafter, the national government held a referendum proposing that an elected president should replace the Gambian monarch (Queen Elizabeth II) as the head of state. This referendum failed to receive the two-thirds majority required to amend the constitution, but the results won widespread attention abroad as testimony to the Gambia's observance of secret balloting, honest elections, civil rights, and liberties. On 24 April 1970, Gambia became a republic within the Commonwealth, following a second referendum. Prime Minister Sir Dawda Kairaba Jawara became the Head of State.
The Gambia was led by President Dawda Jawara, who was re-elected five times. The relative stability of the Jawara era was shattered first by an attempted coup in 1981. The coup was led by Kukoi Samba Sanyang, who, on two occasions, had unsuccessfully sought election to Parliament. After a week of violence which left several hundred people dead, Jawara, in London when the attack began, appealed to Senegal for help. Senegalese troops defeated the rebel force.
In the aftermath of this attempted coup, Senegal and Gambia signed a Treaty of Confederation in 1982. The goal of the Senegambia Confederation was to combine the armed forces of the two states and to unify their economies and currencies. After just a short stretch of years, Gambia permanently withdrew from this confederation in 1989.