Locations
| Name | Sites | Samples |
|---|---|---|
| Saline County | 5 | 12 |
| Salt Lake County | 8 | 67 |
| San Augustine County | 3 | 4 |
| San Miguel County | 1 | 1 |
| San Patricio County | 12 | 52 |
| San Saba County | 3 | 12 |
| Sanpete County | 3 | 12 |
| Santa Rosa County | 6 | 12 |
| Saratoga County | 6 | 13 |
| Saudi Arabia | 1 | 1 |
| Saunders County | 2 | 3 |
| Schenectady County | 3 | 4 |
| Schuyler County | 1 | 1 |
| Scioto County | 9 | 30 |
| Scott County | 1 | 2 |
| Scott County | 4 | 22 |
| Scott County | 1 | 1 |
| Screven County | 6 | 18 |
| Seminole County | 3 | 4 |
| Seminole County | 1 | 2 |
| Seneca County | 8 | 31 |
| Serbia | 4 | 3 |
| Sevier County | 4 | 22 |
| Sharkey County | 5 | 14 |
| Shawano County | 1 | 0 |
| Shawnee County | 1 | 5 |
| Shelby County | 2 | 2 |
| Shelby County | 2 | 4 |
| Shenandoah County | 2 | 4 |
| Sherburne County | 2 | 3 |