Principal Aquifers of the 48 Conterminous United States, Hawaii, Puerto Rico, and the U.S. Virgin Islands
This map layer contains the shallowest principal aquifers of the
conterminous United States, Hawaii, Puerto Rico, and the U.S. Virgin
Islands, portrayed as polygons.  The map layer was developed as part of
the effort to produce the maps published at 1:2,500,000 in the printed
series "Ground Water Atlas of the United …