Coastline of the United States

1. Figures are lengths of general outline of seacoast. This does not include freshwater coastlines. Measurements are made with unit measure of 30 minutes of latitude on charts as near scale of 1:1,200,000 as possible. Coastline of bays and sounds is included to point where they narrow to width of unit measure, and distance across at such point is included.

2. Figures were obtained in 1939–1940 with recording instrument on the largest-scale maps and charts then available. Shoreline of outer coast, offshore islands, sounds, bays, rivers, and creeks is included to head of tidewater, or to point where tidal waters narrow to width of 100 feet.