The Gambia is the smallest State on the African mainland and is shaped unlike any other nation in the world. It is completely surrounded by Senegal, with the exception of a small section of coastline. The boundary is 765 kilometers and is formed by lines of  latitude and longitude as well as a buffer line drawn 10 kilometers from either shore of the Gambia River. The modern-day border dates back to the colonial era, when British and French disputes over the territory, and specifically the Gambia River, led to the uniquely shaped international boundary.

Despite extensive colonial demarcation efforts and post-independence re-demarcation work, there remains some conflict as to the precise alignment of certain border communities as belonging to either Senegal or The Gambia. The two States have an active demarcation commission working on resolving these problem areas.

The Gambia and Senegal also have an established maritime boundary.