| Official Zip Code Name | Williamstown |
| Zip Code State | Missouri |
| Primary County: | Lewis |
| Area Code | 573 |
| Current Population: | 37081 |
| Racial Majority: | White 62.49% |
| Median Household Income | $55618 |
| Average Adjusted Gross Income | $89060 |
| Time Zone: | 6 |
| Elevation Range | 700 ft. |
| Area | 61.883 Sqm. |
| Coordinates(Y,X) | 40.234199, -91.764440 |