Region
- United States 6 results
- Alaska 4 results
- Texas 4 results
- Wisconsin 4 results
- Alabama 2 results
- Albany (Ga.) 2 results
- Atlantic Coast (Del.) 2 results
- Big Thicket 2 results
- Big Thicket (Tex.) 2 results
- California 2 results
- Chile 2 results
- Delaware Bay (Del. and N.J.) 2 results
- Fort Worth (Tex.) 2 results
- Georgia 2 results
- Grand Canyon (Ariz.) 2 results
- Grand Canyon National Park (Ariz.) 2 results
- Hardin County 2 results
- Hardin County (Tex.) 2 results
- Isle Royale 2 results
- Isle Royale (Mich.) 2 results
- Louisiana 2 results
- Michigan 2 results
- Milwaukee 2 results
- Milwaukee (Wis.) 2 results
- Minnesota 2 results
- Napa County 2 results
- Napa County (Calif.) 2 results
- Nebraska 2 results
- New Jersey 2 results
- New Orleans 2 results
- New Orleans (La.) 2 results
- Southern States 2 results
- Utah 2 results
- Virginia 2 results
- Yukon River Valley (Yukon and Alaska) 2 results