The Republic of The Gambia, commonly referred to as The Gambia, or Gambia /ˈɡæmbiə/, is a country in West Africa. Gambia is the smallest country on mainland Africa, surrounded by Senegal except for a short coastline on the Atlantic Ocean in the west.

The country is situated around the Gambia River, the nation's namesake, which flows through the country's centre and empties into the Atlantic Ocean. Its area is almost 10,500 km² with an estimated population of 1,700,000.

On 18 February 1965, Gambia gained independence from the United Kingdom and joined The Commonwealth. Banjul is Gambia's capital, but the largest conurbations are Serekunda and Brikama.

Gambia shares historical roots with many other west African nations in the slave trade, which was the key factor in the placing and keeping of a colony on the Gambia River, first by the Portuguese and later by the British. Since gaining independence in 1965, Gambia has enjoyed relative political stability, with the exception of a brief period of military rule in 1994.

An agriculturally fertile country, its economy is dominated by farming, fishing, and tourism. About a third of the population lives below the international poverty line of US$1.25 a day.

Arab traders provided The Gambia's first written accounts in the 9th and 10th centuries. During the 10th century, Muslim merchants and scholars established communities in several West African commercial centres. Both groups established trans-Saharan trade routes, leading to a large trade in slaves, gold, ivory (exports) and manufactured goods, etc., (imports).

By the 11th century or the 12th century, the rulers of kingdoms such as Takrur (a monarchy centered on the Senegal River just to the north), ancient Ghana and Gao, had converted to Islam and had appointed Muslims who were literate in the Arabic language as courtesans. At the beginning of the 14th century, most of what is today called Gambia was part of the Mali Empire. The Portuguese reached this area by sea in the mid-15th century, and they began to dominate overseas trade.

In 1588, the claimant to the Portuguese throne, António, Prior of Crato, sold exclusive trade rights on the Gambia River to English merchants. Letters patent from Queen Elizabeth I confirmed the grant. In 1618, King James I of England granted a charter to an English company for trade with Gambia and the Gold Coast (now Ghana). Between 1651 and 1661 some parts of Gambia were under Courland's rule, and had been bought by Prince Jacob Kettler, who was a Polish-Lithuanian vassal.

During the late 17th century and throughout the 18th century, the British Empire and the French Empire struggled continually for political and commercial supremacy in the regions of the Senegal River and the Gambia River. The British Empire occupied Gambia when an expedition led by Augustus Keppel landed there—following the Capture of Senegal in 1758. The 1783 First Treaty of Versailles gave Great Britain possession of the Gambia River, but the French retained a tiny enclave at Albreda on the river's north bank. This was finally ceded to the United Kingdom in 1856.

According to its current president Yahya Jammeh, 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 Mexican 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 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 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, Gambia became a separate colony.

An agreement with the French Republic in 1889 established the present boundaries of Gambia. 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). 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, Gambian troops fought with the Allies of World War II. 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 Banju). According to the current president Yahya 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 as 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 February 18, 1965, as a constitutional monarchy within the British 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 Gambia's observance of secret balloting, honest elections, civil rights, and liberties. On April 24, 1970, Gambia became a republic within the Commonwealth, following a second referendum. Prime Minister Sir Dawda Kairaba Jawara became the as Head of State. This made the Gambia both the first and last British colony in West Africa.

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.

In 1994, the Armed Forces Provisional Ruling Council (AFPRC) deposed the Jawara government and banned opposition political activity. Lieutenant Yahya A.J.J. Jammeh, chairman of the AFPRC, became head of state. The AFPRC announced a transition plan for return to democratic civilian government. The Provisional Independent Electoral Commission (PIEC) was established in 1996 to conduct national elections. The PIEC was transformed to the Independent Electoral Commission (IEC) in 1997 and became responsible for registration of voters and conduct of elections and referendums. In late 2001 and early 2002, the Gambia completed a full cycle of presidential, legislative, and local elections, which foreign observers deemed free, fair, and transparent, albeit with some shortcomings. President Yahya Jammeh, who was elected to continue in the position he had assumed during the coup, took the oath of office again on 21 December 2001. Jammeh's Alliance for Patriotic Reorientation and Construction (APRC) maintained its strong majority in the National Assembly, particularly after the main opposition United Democratic Party (UDP) boycotted the legislative elections.

Gambians are known for their excellent music, as well as their dancing. Although the Gambia is the smallest country on mainland Africa, its culture is the product of very diverse influences. The national borders outline a narrow strip on either side of the River Gambia, a body of water that has played a vital part in the nation's destiny and is known locally simply as "the River." Without natural barriers, the Gambia has become home to most of the ethnic groups that are present throughout western Africa, especially those in Senegal. Europeans also figure prominently in the nation's history because the River Gambia is navigable deep into the continent, a geographic feature that made this area one of the most profitable sites for the slave trade from the 15th through the 17th centuries. (It also made it strategic to the halt of this trade once it was outlawed in the 19th century.) Some of this history was popularized in the Alex Haley book and TV series Roots which was set in the Gambia.

The Gambia is a very small and narrow country whose borders mirror the meandering Gambia River. It lies between latitudes 13° and 14°N, and longitudes 13° and 17°W.

The country is less than 48.2 km (30.0 mi) wide at its widest point, with a total area of 11,300 km². Approximately 1,300 km² of The Gambia's area is covered by water. The Gambia is the smallest country on the continent of Africa. In comparative terms the Gambia has a total area which is slightly less than that of the island of Jamaica. The western side of the country borders the North Atlantic Ocean with 50 miles of coastline.

The climate of The Gambia is tropical. There is a hot and rainy season, normally from June until November, but from then until May there are cooler temperatures with less precipitation. The climate in The Gambia is about the same as that found in neighbouring Senegal, southern Mali, and the northern part of Benin.

Its present boundaries were defined in 1889 after an agreement between the United Kingdom and France. During the negotiations between the French and the British in Paris, the French initially gave the British approximately 200 miles (320 km) of the Gambia River to control. Starting with the placement of boundary markers in 1891, it took nearly fifteen years after the Paris meetings to determine the final borders of The Gambia. The resulting series of straight lines and arcs gave the British control of areas that are approximately 10 miles (16 km) north and south of the Gambia River.