Region
- United States 19 results
- Columbia River Watershed 2 results
- Great Britain 2 results
- Illinois Waterway (Ill.) 2 results
- India 2 results
- Mississippi River 2 results
- Central Europe 1 results
- Colorado 1 results
- Eastern Europe 1 results
- Europe centrale 1 results
- Europe de l'Est 1 results
- Europe, Central 1 results
- Europe, Eastern 1 results
- Northeastern States 1 results
- Outer space 1 results
- Patna 1 results
- Pennsylvania 1 results
- Saudi Arabia 1 results