11 zips
| Zip Code | City | Population ↓ |
|---|---|---|
| 66968 | Washington | 1,309 |
| 66945 | Hanover | 1,048 |
| 66937 | Clifton | 928 |
| 66953 | Linn | 634 |
| 66943 | Greenleaf | 590 |
| 66944 | Haddam | 321 |
| 66933 | Barnes | 296 |
| 66958 | Morrowville | 272 |
| 66962 | Palmer | 218 |
| 66946 | Hollenberg | 120 |
| 66955 | Mahaska | 49 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 11 ZCTAs in Washington County, Kansas (US Census).