| Zip Code | City | Population ↓ |
|---|---|---|
| 45750 | Marietta | 26,250 |
| 45714 | Belpre | 9,167 |
| 45742 | Little Hocking | 3,335 |
| 45784 | Vincent | 3,250 |
| 45786 | Waterford | 2,854 |
| 45767 | New Matamoras | 2,598 |
| 45744 | Lowell | 2,234 |
| 45724 | Cutler | 2,190 |
| 45729 | Fleming | 2,111 |
| 45768 | Newport | 1,567 |
| 45788 | Whipple | 975 |
| 45773 | Reno | 533 |
| 45746 | Macksburg | 373 |
| 45789 | Wingett Run | 146 |
| 45721 | Coal Run | 23 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 15 ZCTAs in Washington County, Ohio (US Census).