Which Caribbean federation has Basseterre as its capital?

The Caribbean federation with Basseterre as its capital is Saint Kitts and Nevis.

Saint Kitts and Nevis is a two-island country in the Leeward Islands of the Lesser Antilles. Basseterre stands on the southwestern coast of Saint Kitts, the federation’s larger island, and serves as its political center, principal port, and largest city. Nevis lies southeast of Saint Kitts across a shallow channel known as The Narrows.

The town was founded by the French in 1627 and became an important colonial port. It later changed hands during the rivalry between Britain and France in the Caribbean. Basseterre’s history includes repeated destruction by wars, fires, earthquakes, floods, and hurricanes, so many surviving central buildings date from after a major fire in 1867.

The federation became independent from the United Kingdom in 1983. It is the smallest sovereign federation in the world and the smallest sovereign state in the Western Hemisphere by both area and population. Basseterre is sometimes confused with Basse-Terre, the capital of Guadeloupe, but they are different Caribbean places.