Waterway for small craft extending in two sections from Boston, Mass., to Brownsville, Tex.: it consists of natural and artificial channels within the U.S. coastline except for a stretch of open water along the W Fla. coast: 2,500 to 3,000 mi (4,023 to 4,828 km) long.
Webster's New World
A system of artificial and natural channels and canals along the eastern and southeast coasts of the United States. It includes the Atlantic Intracoastal Waterway and the Gulf Intracoastal Waterway and affords sheltered passage for commercial and pleasure craft.