System of inland waterways, including rivers and canals, along the U.S. coast of the Gulf of Mexico .
It extends from Apalachee Bay, Fla., west to the Mexican border at Brownsville, Texas, a distance of more than 1,100 mi (1,770 km). It includes Mobile Bay and Mississippi Sound, passes through New Orleans , and takes in the Sabine-Neches Waterway and the ship canal at Houston . Together with its counterpart, the Atlantic Intracoastal Waterway , it forms the Intracoastal Waterway, a shipping route that extends for 3,000 mi (4,800 km) in the southern and eastern U.S.