Founded in 1854, Mason County is one of 39 counties in the state of Washington. Historically, Mason County was formed from King County. The city of Shelton is the county seat. With FIPS code of 45, Mason County has a population of 65,726 and area of 959 square miles (2,484 km2).
List of all cities in Mason County, WA alphabetically
| City/Town | Postal Code | Area Code |
| Allyn, WA | 98524 | 360/564 |
| Belfair, WA | 98528 | 360/564 |
| Cushman Dam, WA | 98548 | 360/564 |
| Eldon, WA | 98555 | 360/564 |
| Grapeview, WA | 98546 | 360/564 |
| Harstine, WA | 98584 | 360/564 |
| Hoodsport, WA | 98548 | 360/564 |
| Kamilche, WA | 98584 | 360/564 |
| Lilliwaup, WA | 98555 | 360/564 |
| Matlock, WA | 98560 | 360/564 |
| Shelton, WA | 98584 | 360/564 |
| Skok, WA | 98584 | 360/564 |
| Skokomish, WA | 98584 | 360/564 |
| Skokomish Nation, WA | 98584 | 360/564 |
| Tahuya, WA | 98588 | 360/564 |
| Union, WA | 98592 | 360/564 |