Sub-locations
| Name | Sites | Samples |
|---|---|---|
| Beaverhead County | 6 | 19 |
| Big Horn County | 43 | 300 |
| Blaine County | 3 | 6 |
| Broadwater County | 7 | 56 |
| Carbon County | 19 | 123 |
| Carter County | 3 | 22 |
| Cascade County | 6 | 29 |
| Chouteau County | 16 | 44 |
| Custer County | 5 | 5 |
| Dawson County | 15 | 49 |
| Deer Lodge County | 2 | 7 |
| Fallon County | 2 | 3 |
| Fergus County | 7 | 40 |
| Flathead County | 1 | 1 |
| Gallatin County | 6 | 12 |
| Garfield County | 5 | 8 |
| Glacier County | 4 | 51 |
| Golden Valley County | 2 | 24 |
| Granite County | 1 | 4 |
| Hill County | 10 | 57 |
| Jefferson County | 7 | 56 |
| Judith Basin County | 1 | 1 |
| Lewis and Clark County | 9 | 19 |
| Liberty County | 2 | 3 |
| Lincoln County | 18 | 80 |