Country: Minnesota, Iowa, Missouri
Distribution of Terrestrial Snakes in North America
Pit Vipers
| Agkistrodon contortrix | S | Iowa, Missouri |
| Agkistrodon piscivorus | S | S Missouri |
| Crotalus horridus | C+S | |
| Crotalus viridis | NW? | Western Iowa only |
| Sistrurus catenatus | X | E Iowa, NE Missouri |
| Sistrurus miliarius | S | Missouri only |
| Sistrurus tergeminus | X | SW Iowa, NW Missouri |