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USGS Water Science Centers are located in each state.

 [Map: There is a USGS Water Science Center office in each State.] Washington Oregon California Idaho Nevada Montana Wyoming Utah Colorado Arizona New Mexico North Dakota South Dakota Nebraska Kansas Oklahoma Texas Minnesota Iowa Missouri Arkansas Louisiana Wisconsin Illinois Mississippi Michigan Indiana Ohio Kentucky Tennessee Alabama Pennsylvania West Virginia Georgia Florida Caribbean Alaska Hawaii and Pacific Islands New York Vermont New Hampshire Maine Massachusetts South Carolina North Carolina Rhode Island Virginia Connecticut New Jersey Maryland-Delaware-D.C.

National Aquifer Code Reference List

National aquifers, or principal aquifers of the United States, are defined as regionally extensive aquifers or aquifer systems that have the potential to be used as a source of potable water. The first publication of the core of the national aquifer list in a comprehensive manner was the Ground-Water Atlas of the United States (USGS Hydrologic Atlas 730 A-H), published in 13 chapters over the period 1990-1999, James A. Miller, editor.

A single combined map (Principal Aquifers) was published as part of the National Atlas in 1998, revised 2003.

Aquifers shown on the 2003 Principal Aquifers map, with some additions, were used as the first National Aquifer reference list in the USGS National Water Information System (NWIS) in the Aggregate Water Use Data System (database released in August 2001). In 2005, national aquifer was added as a field to the other components of NWIS, and to NWISWeb. Entries with a gray background are no longer valid.

Reference List
Code components


Aquifer Name Code Valid States Link to Aquifer Basics site
Ada-Vamoosa aquifer N300ADAVMS Oklahoma Ada-Vamoosa aquifer (Oklahoma)
Alaska unconsolidated-deposit aquifers N100AKUNCD Alaska Unconsolidated-deposit aquifers (Alaska)
Alluvial aquifers N100ALLUVL Arkansas, Colorado, Delaware, Kansas, Kentucky, Louisiana, Maryland, Missouri, Montana, Nebraska, New Jersey, North Dakota, Ohio, Oklahoma, South Dakota, Tennessee, Texas, Utah, Virginia, West Virginia, Wyoming See note in History
Arbuckle-Simpson aquifer N400ABKSMP Oklahoma Arbuckle-Simpson aquifer (Oklahoma)
Basin and Range basin-fill aquifers N100BSNRGB Arizona, California, Idaho, Nevada, New Mexico, Oregon, Utah Basin and Range basin-fill aquifers (southwestern U.S.)
Basin and Range carbonate-rock aquifers N400BSNRGC Arizona, California, Idaho, Nevada, Utah Basin and Range carbonate-rock aquifers (southwestern U.S.)
Biscayne aquifer N400BISCYN Florida Biscayne aquifer (Florida)
Blaine aquifer N400BLAINE Oklahoma, Texas Blaine aquifer (Oklahoma and Texas)
California Coastal Basin aquifers N100CACSTL California California Coastal Basin aquifers
Cambrian-Ordovician aquifer system S300CAMORD Illinois, Iowa, Michigan, Minnesota, Missouri, Wisconsin Cambrian-Ordovician aquifer system (northern Midwest)
Castle Hayne aquifer N400CSLHYN North Carolina Castle Hayne aquifer (North Carolina)
Central Oklahoma aquifer N300CNRLOK Oklahoma Central Oklahoma aquifer
Central Valley aquifer system S100CNRLVL California Central Valley aquifer system (California)
Coastal lowlands aquifer system S100CSLLWD Alabama, Florida, Louisiana, Mississippi, Texas Coastal lowlands aquifer system (Gulf Coast)
Colorado Plateaus aquifers N300COPLTS Arizona, Colorado, New Mexico, Utah, Wyoming Colorado Plateaus aquifers
Columbia Plateau basaltic-rock aquifers N600CMBPLV Idaho, Oregon, Washington Columbia Plateau basaltic-rock aquifers
Columbia Plateau basin-fill aquifers N100CMBPLB Idaho, Oregon, Washington Columbia Plateau basin-fill aquifers
Denver Basin aquifer system S300DNVRBS Colorado Denver Basin aquifer system
Early Mesozoic basin aquifers N300ERLMZC Connecticut, Maryland, Massachusetts, New Jersey, New York, North Carolina, Pennsylvania, Virginia Early Mesozoic basin aquifers (eastern U.S.)
Edwards-Trinity aquifer system S500EDRTRN Arkansas, Oklahoma, Texas Edwards-Trinity aquifer system (Texas and Oklahoma)
Floridan aquifer system S400FLORDN Alabama, Florida, Georgia, South Carolina Floridan aquifer system
Hawaii volcanic-rock aquifers N600HIVLCC Hawaii Hawaiian aquifers (Hawaii)
High Plains aquifer N100HGHPLN Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, Wyoming High Plains aquifer
Intermediate aquifer system S500INTRMD Florida GW Atlas: Intermediate aquifer system (Florida)
Jacobsville aquifer N300JCBSVL Michigan, Wisconsin Jacobsville aquifer (Michigan)
Kingshill aquifer (Virgin Islands) N400KNGSHL Virgin Islands Kingshill aquifer (Virgin Islands)
Lower Cretaceous aquifers N300LCRTCS Iowa, Kansas, Minnesota, Montana, Nebraska, North Dakota, South Dakota, Wyoming Lower Cretaceous aquifers (northern Great Plains)
Lower Tertiary aquifers N300LTRTRY Montana, North Dakota, South Dakota, Wyoming Lower Tertiary aquifers (northern Great Plains)
Marshall aquifer N300MRSHLL Michigan Marshall aquifer (Michigan)
Mississippi embayment aquifer system S100MSEMBM Alabama, Arkansas, Illinois, Kentucky, Louisiana, Mississippi, Missouri, Tennessee, Texas Mississippi embayment aquifer system
Mississippi River Valley alluvial aquifer N100MSRVVL Arkansas, Illinois, Kentucky, Louisiana, Mississippi, Missouri, Tennessee Mississippi River Valley alluvial aquifer
Mississippian aquifers N500MSSPPI Alabama, Illinois, Indiana, Iowa, Kentucky, Maryland, Missouri, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia Mississippian aquifers (central and eastern U.S.)
New England crystalline-rock aquifers N600NECRSN Connecticut, Maine, Massachusetts, New Hampshire, New York, Rhode Island, Vermont GW Atlas: Crystalline-rock aquifers (New York and New England)
New York and New England carbonate-rock aquifers N400NYNECB Connecticut, Maine, Massachusetts, New Jersey, New York, Pennsylvania, Vermont New York and New England carbonate-rock aquifers
New York sandstone aquifers N300NYSDSN New York New York sandstone aquifers
North Coast Limestone aquifer system (Puerto Rico) N400NCSTLM Puerto Rico North Coast Limestone aquifer system (Puerto Rico)
Northern Atlantic Coastal Plain aquifer system S100NATLCP Delaware, District of Columbia, Maryland, New Jersey, New York, North Carolina, Pennsylvania, Virginia Northern Atlantic Coastal Plain aquifer system
Northern Great Plains aquifer system (no longer valid) S500NGRTPL Montana, North Dakota, South Dakota, Wyoming (Includes four national aquifers but is not considered a national aquifer itself. The component aquifers are Lower Tertiary, Upper Cretaceous, Lower Cretaceous, and Paleozoic.)
Northern Rocky Mountains Intermontane Basins aquifer systems S100NRMTIB Idaho, Montana, Washington, Wyoming Northern Rocky Mountains Intermontane Basins aquifer system
Ordovician aquifers N400ORDVCN Kentucky, Tennessee Ordovician aquifers (Tennessee and Kentucky)
Other aquifers N9999OTHER All Other aquifers
Ozark Plateaus aquifer system S400OZRKPL Arkansas, Illinois, Kansas, Missouri, Oklahoma Ozark Plateaus aquifer system (Missouri)
Pacific Northwest basin-fill aquifers N100PCFNWB California, Idaho, Nevada, Oregon, Utah, Washington, Wyoming Pacific Northwest basin-fill aquifers
Pacific Northwest volcanic-rock aquifers N100PCFNWV California, Idaho, Montana, Nevada, Oregon, Utah, Washington, Wyoming Pacific Northwest basaltic-rock aquifers
Paleozoic aquifers N500PLOZOC Minnesota, Montana, North Dakota, South Dakota, Wyoming Paleozoic aquifers (northern Great Plains)
Pecos River Basin alluvial aquifer N100PCSRVR New Mexico, Texas Pecos River Basin alluvial aquifer (Texas and New Mexico)
Pennsylvanian aquifers N300PNSLVN Alabama, Georgia, Illinois, Indiana, Kentucky, Maryland, Michigan, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia Pennsylvanian aquifers (central and eastern U.S.)
Piedmont and Blue Ridge carbonate-rock aquifers N400PDMBRC Maryland, New Jersey, North Carolina, Pennsylvania Piedmont and Blue Ridge carbonate-rock aquifers (eastern U.S.)
Piedmont and Blue Ridge crystalline-rock aquifers N400PDMBRX Alabama, Delaware, District of Columbia, Georgia, Maryland, New Jersey, New York, North Carolina, Pennsylvania, South Carolina, Tennessee, Virginia, West Virginia Piedmont and Blue Ridge crystalline-rock aquifers (eastern U.S.)
Puget Sound aquifer system S100PGTSND Washington Puget Sound aquifer system (Washington)
Rio Grande aquifer system S100RIOGRD Colorado, New Mexico, Texas Rio Grande aquifer system
Roswell Basin aquifer system S400RSWLBS New Mexico Roswell Basin aquifer system (New Mexico)
Rush Springs aquifer N300RSHSPG Oklahoma Rush Springs aquifer (Oklahoma)
Sand and gravel aquifers (glaciated regions) N100GLCIAL Connecticut, Illinois, Indiana, Iowa, Kansas, Kentucky, Maine, Massachusetts, Michigan, Minnesota, Missouri, Montana, Nebraska, New Hampshire, New Jersey, New York, North Dakota, Ohio, Pennsylvania, Rhode Island, South Dakota, Vermont, Wisconsin Sand and gravel aquifers of alluvial and glacial origin (North of the line of glaciation)
Seymour aquifer N100SYMOUR Texas Seymour aquifer (Texas)
Silurian-Devonian aquifers N400SLRDVN Illinois, Indiana, Iowa, Kentucky, Michigan, Missouri, Ohio, Tennessee, Wisconsin Silurian-Devonian aquifers (northern Midwest)
Snake River Plain basaltic-rock aquifers N600SKRVPV Idaho, Oregon Snake River Plain basaltic-rock aquifers (Idaho)
Snake River Plain basin-fill aquifers N600SKRVPB Idaho, Oregon Snake River Plain basin-fill aquifers (Idaho)
South Coast aquifer (Puerto Rico) N300STHCST Puerto Rico South Coast aquifer (Puerto Rico)
Southeastern Coastal Plain aquifer system S100SECSLP Alabama, Georgia, Mississippi, South Carolina, Tennessee Southeastern Coastal Plain aquifer system
Southern Nevada volcanic-rock aquifers N600SRNVDV Nevada Southern Nevada volcanic-rock aquifers
Surficial aquifer system S100SURFCL Alabama, Florida, Georgia, North Carolina, South Carolina Surficial aquifer system (eastern U.S.)
Texas coastal uplands aquifer system S100TXCLUP Louisiana, Texas Texas coastal uplands aquifer system
Upper carbonate aquifer N400UPCRBN Iowa, Minnesota

Upper carbonate aquifer (Minnesota and Iowa)

Upper Cretaceous aquifers N300UPCTCS Montana, North Dakota, South Dakota, Wyoming Upper Cretaceous aquifers (northern Great Plains)
Valley and Ridge aquifers N500VLYRDG Alabama, Georgia, Maryland, New Jersey, New York, North Carolina, Pennsylvania, Tennessee, Virginia, West Virginia Valley and Ridge aquifers (eastern U.S.)
Valley and Ridge carbonate-rock aquifers (No longer valid) N500VLRDGC Alabama, Georgia, Maryland, New Jersey, Pennsylvania, Tennessee, Virginia, West Virginia (Should be included in Valley and Ridge aquifers.)
Willamette Lowland basin-fill aquifers N100WLMLWD Oregon, Washington Willamette Lowland basin-fill aquifers (Oregon)
Wyoming Tertiary aquifers N300WYTRTR Wyoming Upper Tertiary aquifers (Wyoming)

Code components:

N or S, where N = aquifer, S = aquifer system
3 digit number = rock type (4 digits used for "Other" to fill out the code)
6 character identifier derived from the aquifer name .

Rock types are:

100-- Sand and gravel aquifers
200--Semiconsolidated sand aquifers (not used)
300--Sandstone aquifers
400--Carbonate-rock aquifers
500--Sandstone and carbonate-rock aquifers
600--Igneous and metamorphic-rock aquifers
9999--Areas that are not a national aquifer.

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Page Last Modified: Tuesday, 29-Oct-2013 14:44:41 EDT