The Gambia is a very small and narrow country whose borders mirror the meandering Gambia River. The country is less than 48 km 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. It is almost an enclave of Senegal, with all of the 740 km border zones touching Senegal. 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 80 km of coastline.

The general climate for the Gambia is tropical. During the period from June until November, there is a period of hot weather and a very rainy season. From November until May, there are cool temperatures and is part of a dry season. The climate in the Gambia is the same found in neighboring 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 boundary 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.