The National Atlas of the United States is offering a beautiful, new map showing the principal aquifers that supply subsurface or "ground" water to the United States, Puerto Rico, and the U. S. Virgin Islands. The new aquifer map shows State boundaries, major cities, and surface-water features. The map measures 30x42 inches and it is impressive when it is framed for display or for quick everyday reference. To see this and hundreds of other maps from the National Atlas, please visit http://nationalatlas.gov/. For more information on ground water visit the USGS website http://water.usgs.gov/ogw/.