Sub-locations
| Name | Sites | Samples |
|---|---|---|
| Arkansas County | 3 | 7 |
| Ashley County | 4 | 13 |
| Baxter County | 1 | 1 |
| Benton County | 13 | 38 |
| Bradley County | 1 | 1 |
| Calhoun County | 2 | 14 |
| Carroll County | 4 | 16 |
| Chicot County | 3 | 6 |
| Clark County | 8 | 25 |
| Clay County | 1 | 3 |
| Conway County | 3 | 18 |
| Craighead County | 5 | 11 |
| Crawford County | 5 | 10 |
| Crittenden County | 13 | 100 |
| Cross County | 6 | 28 |
| Drew County | 5 | 7 |
| Hempstead County | 4 | 31 |
| Hot Spring County | 5 | 12 |
| Howard County | 2 | 6 |
| Independence County | 1 | 4 |
| Jackson County | 2 | 8 |
| Lafayette County | 7 | 27 |
| Lawrence County | 0 | 0 |
| Lee County | 3 | 7 |
| Little River County | 3 | 5 |