This map layer shows major ports in the United States, Puerto Rico, and the U.S. Virgin Islands. A port is a city, town, or urban area with a harbor where ships load or unload. This is a revised version of the July 2012 map layer. This layer is part of the 1997-2014 edition of the National Atlas of the United States.These data are intended for geographic display and analysis at the national level, and for large regional areas. The data should be displayed and analyzed at scales appropriate for 1:1,000,000-scale data. No responsibility is assumed by the National Atlas of the United States in the use of these data.