| Place Name | Williamstown |
| Place Type | Census Designated Place |
| ZIP Code(s) | 63473 |
| County | Lewis County |
| Area Code(s) | 573 |
| Timezone | Central Standard Time (CST) |
| Population (2022) | 84 |
| Majority Ethnicity | White 100% |
| Metro/Micro Stats Area | Quincy, IL-MO |
| US Congressional District(s) | Missouri 6th |
| State House Districts | 4 |
| State Senate Districts | 18 |
| Race/Ethnicy | Percentage of Population (2021) |
|---|---|
| White | 100% |
| African American | 0% |
| Hispanic | 0% |
| Asian | 0% |
| Native American | 0% |
| Hawaiin/Pacific Islander | 0% |