The greatest reef development in México is found in its Caribbean reefs which are principally of the fringing type. Extending for over 350 km along the coast of the state of Quintana Roo they comprise the northernmost part of the Mesoamerican Reef System which continues through the neighboring countries of Belize, Guatemala and Honduras. The 20 coral reefs of the Veracruz Reef System are located within 22 km of the coast near the Port of Veracruz in the western Gulf of Mexico. The reefs developed on the continental shelf after the last glacial period some 9,000 to 10,000 years ago.