Sub-locations
| Name | Sites | Samples |
|---|---|---|
| Beaverhead County | 5 | 16 |
| Big Horn County | 33 | 158 |
| Blaine County | 3 | 6 |
| Broadwater County | 6 | 54 |
| Carbon County | 13 | 98 |
| Carter County | 3 | 16 |
| Cascade County | 5 | 28 |
| Chouteau County | 15 | 43 |
| Custer County | 5 | 5 |
| Dawson County | 14 | 37 |
| Deer Lodge County | 2 | 6 |
| Fallon County | 2 | 3 |
| Fergus County | 5 | 32 |
| Flathead County | 1 | 1 |
| Gallatin County | 4 | 8 |
| Garfield County | 4 | 7 |
| Glacier County | 1 | 1 |
| Golden Valley County | 2 | 18 |
| Hill County | 9 | 51 |
| Jefferson County | 6 | 49 |
| Judith Basin County | 1 | 1 |
| Lewis and Clark County | 7 | 17 |
| Liberty County | 1 | 2 |
| Lincoln County | 17 | 79 |
| Madison County | 2 | 4 |