The Atlantic Ocean is on the East Coast of the United States. The East Coast region encompasses the coastline where the Eastern United States meets the Atlantic Ocean, and it is also known as the Eastern Seaboard, the Atlantic Coast, and the Atlantic Seaboard. The 14 states that have a shoreline on the Atlantic Ocean are Maine, New Hampshire, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, Delaware, Maryland, Virginia, North Carolina, South Carolina, Georgia, and Florida. Pennsylvania and Washington, D.C. border the Delaware River and the Potomac River, respectively, both of which are tidal arms of the Atlantic Ocean.