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Region
- PennsylvaniaChester County7
- Arkansas3
- Delaware3
- Louisiana3
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- New Jersey3
- High Plains (U.S.)2
- High Plains Aquifer2
- NevadaNevada National Security Site2
- New Mexico2
- Rio Grande Valley2
- Santa Fe Group2
- TexasEdwards Plateau Region2
- TexasTrinity River Watershed2
- American SamoaTutuila Island1
- CaliforniaAntelope Valley1
- CaliforniaMojave River Watershed1
- CaliforniaSan Bernardino County1
- DelawareNew Castle County1
- IdahoBoise Region1