11 zips
| Zip Code | City | Population ↓ |
|---|---|---|
| 66968 | Washington | 1,435 |
| 66945 | Hanover | 987 |
| 66937 | Clifton | 919 |
| 66953 | Linn | 611 |
| 66943 | Greenleaf | 582 |
| 66944 | Haddam | 330 |
| 66933 | Barnes | 299 |
| 66958 | Morrowville | 272 |
| 66962 | Palmer | 223 |
| 66946 | Hollenberg | 113 |
| 66955 | Mahaska | 40 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 11 ZCTAs in Washington County, Kansas (US Census).