| Beaver Drainage District |
| Clatskanie Drainage District |
| Deer Island Drainage District |
| Inland Drainage District |
| John Drainage District |
| Kerry Island Drainage District |
| Magruder Drainage District |
| Marshland Drainage District |
| Midland Drainage District |
| Palm Drainage District |
| Prescott Drainage District |
| Rainier Drainage District |
| Sauvie Island Drainage District |
| Scappoose Drainage District |
| Webb Drainage District |
| Westland Drainage District |
| Westport Drainage District |
| Woodson Drainage District |
