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Aquifers: Map of the Principal Aquifers of the United States
The areal and vertical location of the major aquifers is fundamental to the determination of groundwater availability for the Nation. An aquifer is a geologic formation, a group of formations, or a part of a formation that contains sufficient saturated permeable material to yield significant quantities of water to wells and springs.
A two-dimensional map representation of the principal aquifers of the Nation is shown below. The map, which is derived from the Ground Water Atlas of the United States, indicates the areal extent of the uppermost principal aquifers on a national scale. In this map, a principal aquifer is defined as a regionally extensive aquifer or aquifer system that has the potential to be used as a source of potable water. (For study or mapping purposes, aquifers are often combined into aquifer systems.)
Principal aquifers of the United States (modified from Principal Aquifers, U.S. Geological Survey, 2003). Download PDF of map with explanation [1.7MB PDF].
The principal aquifers map was published in 2003 as a wall map:
Overview of the Principal Aquifers: Aquifer Basics
The Aquifer Basics web site provides a general overview and maps of the principal aquifers of the United states by rock type and via alphabetical list. The Aquifer Basics web site provides a general summary of information published in the Ground Water Atlas of the United States.
GIS files for the map of the principal aquifers of the United States were released as part of the National Atlas, which was discontinued in late 2014. The National Atlas included two nationwide maps of principal aquifers:
The geosptial files below were downloaded from the National Atlas by the USGS Office of Groundwater in September 2014. The geospatial data files were not updated or revised and reflect their original content from when they were published in 2002 and 2003. For information about how the geospatial data files were originally generated, refer to the metadata files.
More recent geospatial data are available for selected principal aquifers as the result of recent and ongoing regional groundwater availability studies investigated by the Groundwater Resources Program (GWRP) to improve our understanding of groundwater availability in major aquifers across the Nation.
Principal Aquifers of the United States
This dataset, published in 2003, 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 States. The published maps contain base and cultural features not included in these data.
Please note that the maps do not show the entire extent of an aquifer, only its subcrop or outcrop area. Refer to the metadata for a complete description of the files and how they were generated.
Aquifers of Alluvial and Glacial Origin
This dataset, published in 2002, represents the extent of the alluvial and glacial aquifers north of the southern-most line of glaciation. Aquifers are shown in the States of Maine, Vermont, New Hampshire, Connecticut, Massachusetts, Rhode Island, New Jersey, New York, Pennsylvania, Ohio, Indiana, Michigan, Wisconsin, Illinois, Minnesota, Iowa, Missouri, Kansas, Nebraska, South Dakota, North Dakota, and Montana. These data delineate the areal extent of the alluvial and glacial aquifers as defined in The Ground Water Atlas of The United States. Refer to the metadata for a complete description of the files and how they were generated.