Channel in the U.S. through which the James , Elizabeth, and Nansemond rivers flow into Chesapeake Bay .
About 4 mi (6 km) wide and 40 ft (12 m) deep, it has been an important military base since colonial days. In 1862 it was the scene of the Battle of the Newport News , Norfolk , and Portsmouth comprise the Port of Hampton Roads, one of the busiest U.S. seaports.