Region
United States
71
Alaska
20
Colorado
20
California
12
Russia (Federation)
10
China
9
Gulf Coast (U.S.)
8
Arctic Ocean
7
Mexico, Gulf of
5
National Petroleum Reserve
5
Wyoming
5
Arctic National Wildlife Refuge (Alaska)
4
India
4
Mexico
4
National Petroleum Reserve (Alaska)
4
Siberia
4
Utah
4
Arctic National Wildlife Refuge
3
Argentina
3
Australia
3
East (U.S.)
3
Midland Basin (Tex. and N.M.)
3
Montana
3
New Mexico
3
Pakistan
3
Powder River Basin (Wyo. and Mont.)
3
Texas
3
Afghanistan
2
Africa, North
2
Appalachian Region
2
Bakken Formation
2
Europe
2
Great Plains
2
Illinois Basin
2
Indus River Watershed
2
Iraq
2
Junggar Basin
2
Kern County
2
Libya
2
Middle West
2
New Albany Shale (Ind. and Ky.)
2
North Sea
2
North Slope
2
Northwestern States
2
Ordos Desert
2
Pacific Coast (U.S.)
2
Poland
2
San Joaquin Valley
2
Saudi Arabia
2
Siberia, Western
2
more ...