Region
United States
1,764
Colorado
43
California
24
China
19
North America
16
Great Lakes (North America)
12
Mexico
12
West (U.S.)
12
Alaska
11
Developing countries
10
Oregon
10
North Carolina
9
Montana
8
Arctic regions
7
Arizona
7
Asia
7
Gold King Mine (San Juan County, Colo.)
7
Latin America
7
Mexican-American Border Region
7
New Mexico
7
West Virginia
7
Africa South of the Sahara
6
Europe
6
India
6
Louisiana
6
Navajo Nation, Arizona, New Mexico & Utah
6
Texas
6
Chesapeake Bay Watershed
5
Florida
5
Great Lakes Region (North America)
5
Libby
5
Mexico, Gulf of
5
Michigan
5
Nevada
5
New York (State)
5
South Asia
5
Southern Ute Indian Tribe of the Southern Ute Reservation, Colorado
5
Southwestern States
5
Washington (D.C.)
5
Wyoming
5
Africa
4
Chesapeake Bay (Md. and Va.)
4
Earth (Planet)
4
Europe, Eastern
4
Great Britain
4
Idaho
4
Illinois
4
Japan
4
Kansas
4
Middle Atlantic States
4
more ...