The four letter solution for the term 'Atlantic Coast States, with 'the'' is 'EAST'. This refers to the states located on the eastern seaboard of the United States, commonly referred to as the 'EAST Coast' or the 'Atlantic Coast'. These states include Maine, New Hampshire, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, Pennsylvania, Delaware, Maryland, Virginia, North Carolina, South Carolina, Georgia, and Florida.