A large basin between United States and Mexican territory; is shut in by the peninsulas of Florida and Yucatan, 500 m. apart, and the western extremity of Cuba, which lies between them; it receives the Mississippi, Rio Grande, and many other rivers; the coasts are low, with many lagoons; ports like New Orleans, Havana, and Vera Cruz make it a highway for ships; north-easterly hurricanes blow in March and October.