Region
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Iran
7
Mexican-American Border Region
7
Mississippi
7
Nicaragua
7
North Carolina
7
Peru
7
Platte River
7
Saint Louis
7
South Platte River Watershed (Colo. and Neb.)
7
Tennessee
7
Vietnam
7
Asia, Central
6
Belgium
6
Connecticut
6
Greece
6
High Plains
6
Homestead National Monument of America (Neb.)
6
Kentucky
6
Los Angeles
6
Maine
6
Manitoba
6
Mexico City (Mexico)
6
Northwest Territories
6
Northwest, Old
6
Ohio River Valley
6
Rocky Mountains
6
Rosebud Indian Reservation (S.D.)
6
Saint Louis (Mo.)
6
San Francisco (Calif.)
6
États-Unis
6
Agate Fossil Beds National Monument (Neb.)
5
Alabama
5
Amazon River Region
5
Austria
5
California, Southern
5
Canada, Western
5
Dominican Republic
5
Massachusetts
5
Mediterranean Region
5
Minnesota
5
Mississippi River Watershed
5
New York (N.Y.)
5
Oaxaca (Mexico : State)
5
Oceania
5
Ogallala Aquifer
5
Oregon National Historic Trail
5
Pine Ridge Indian Reservation
5
Platte River (Neb.)
5
Prairie Provinces
5
Puerto Rico
5
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