The Federation of Saint Kitts and Nevis (), also known as the Federation of Saint Christopher and Nevis, is a two-island country in the West Indies, in the Caribbean. Located in the Leeward Islands chain of the Lesser Antilles, it is the smallest sovereign state in the Western Hemisphere, in both area and population. The country is a Commonwealth realm, with the British monarch, who is currently Queen Elizabeth II, as head of state.
The capital city is Basseterre on the larger island of Saint Kitts. The smaller island of Nevis lies approximately 3 km (2 mi) southeast of Saint Kitts across a shallow channel called "The Narrows".
The British dependency of Anguilla was historically also a part of this union, which was then known collectively as Saint Christopher-Nevis-Anguilla. To the north-northwest lie the islands of Sint Eustatius, and Saba (the Netherlands), Saint Barthélemy, Saint-Martin/Sint Maarten and Anguilla. To the east and northeast are Antigua and Barbuda, and to the southeast is the small uninhabited island of Redonda, and the island of Montserrat, which currently has an active volcano (see Soufrière Hills).
Saint Kitts and Nevis were among the first islands in the Caribbean to be settled by Europeans. Saint Kitts was home to the first British and French colonies in the Caribbean, and thus has also been titled "The Mother Colony of the West Indies".