Region
United States
États-Unis
18
Maryland
6
North America
6
New Jersey
5
New York (State)
5
America
4
Canada
4
Hanover County (Va.)
4
South Carolina
3
Amerika
2
Amherst County (Va.)
2
Asia
2
Brunswick County (N.C.)
2
Campbell County (Va.)
2
Developing countries
2
Europe
2
Fauquier County (Va.)
2
Fort Clinton (Rockland Co., N.Y.)
2
Fort Montgomery (N.Y.)
2
Georgia
2
Great Britain
2
King William County (Va.)
2
Lenoir County (N.C.)
2
Magothy Aquifer
2
Nelson County (Va.)
2
Patapsco Aquifer
2
Prince George County (Va.)
2
Rocky Mountains
2
Southampton County (Va.)
2
Sussex County (Va.)
2
UNITED STATES OF AMERICA
2
Virginia
2
West (U.S.)
2
AMERICA
1
Alaska
1
Albany County (N.Y.)
1
Allegheny Mountains
1
Amelia County (Va.)
1
Amérique
1
Amérique du Nord
1
Botetourt County (Va.)
1
Brunswick County (Va.)
1
CANADA
1
Chesterfield County (Va.)
1
Columbia (Fleuve)
1
Columbia River
1
Connecticut
1
Connecticut River Watershed
1
Constitution Island (N.Y.)
1
more ...