Saint Martin is the Caribbean island divided between France and the Kingdom of the Netherlands.
The northern part is the French collectivity of Saint-Martin, while the southern part is Sint Maarten, a constituent country within the Kingdom of the Netherlands. The island is among the world’s best-known examples of a peaceful international division.
The boundary was established by the Treaty of Concordia in 1648. Unlike many borders, it is generally open to movement, and visitors can travel between the two sides without a routine border checkpoint. The two administrations nevertheless have separate laws, public services, currencies in common use, and political systems.
A common mix-up is treating “Saint Martin” and “Sint Maarten” as interchangeable names. Saint Martin commonly refers to the whole island or its French side, whereas Sint Maarten specifically identifies the Dutch side.