Founded in 1879, Washington County is one of 44 counties in the state of Idaho. Historically, Washington County was formed from Ada County. The city of Weiser is the county seat. With FIPS code of 87, Washington County has a population of 10,898 and area of 1,456 square miles (3,771 km2).
List of all cities in Washington County, ID alphabetically
| City/Town | Postal Code | Area Code |
| Alpine, ID | 83610 | 208 |
| Cambridge, ID | 83610 | 208 |
| Crystal, ID | 83672 | 208 |
| Eaton, ID | 83672 | 208 |
| Jonathan, ID | 83672 | 208 |
| Midvale, ID | 83645 | 208 |
| Weiser, ID | 83672 | 208 |