Region
United States
223
Colorado
13
Canada
3
Africa
2
Burkina Faso
2
Great Britain
2
La Plata County
2
Niger
2
Alaska
1
Chad
1
Colorado River Watershed (Colo.-Mexico)
1
Djibouti
1
Ethiopia
1
Ireland
1
Kenya
1
Maryland
1
Mauritania
1
Mexican-American Border Region
1
Mozambique
1
Northern Ireland
1
Tanzania
1
West (U.S.)
1
Zambia
1
Zimbabwe
1