St. Lucia is an island in the Caribbean Sea near the Atlantic Ocean, between St. Vincent and Martinique, northwest of Barbados, and south of Antigua, and is midway down the Winward Islands in the Lesser Antilles. Its 13.9°N latitude places it in the tropical zone along the 61.0°W longitudinal line.
St. Lucia is a small island 27 miles long and 14 miles wide. About one-third of the population lives in its capital city, Castries. St. Lucia has rainforests on its mountainous, volcanic terrain. Since it is a volcanic island, its coastlines are steep, dropping off to offer near-shore snorkeling by coral reefs.