Part of the archipelago of the Antilles, Martinique is located in the Caribbean Sea about 450 km (280 mi) northeast of the coast of South America and about 700 km (435 mi) southeast of the Dominican Republic. It is directly north of St. Lucia, northwest of Barbados, and south of Dominica.he total area of Martinique is 1,100 square kilometres (420 sq mi), of which 40 square kilometres (15 sq mi) is water and the rest land. Martinique is the 3rd largest island in The Lesser Antilles after Trinidad and Guadeloupe.