| Official Name: | Williamson, Pennsylvania |
| Settlement Type: | Unincorporated community |
| Pushpin Map: | Pennsylvania#USA |
| Pushpin Label: | Williamson |
| Pushpin Label Position: | top |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Pennsylvania |
| Subdivision Type2: | County |
| Subdivision Name2: | Franklin |
| Subdivision Type3: | Township |
| Subdivision Name3: | St. Thomas |
| Timezone: | Eastern (EST) |
| Utc Offset: | -5 |
| Timezone Dst: | EDT |
| Utc Offset Dst: | -4 |
| Elevation Ft: | 489 |
| Coordinates: | 39.8531°N -77.7975°W |
| Postal Code Type: | ZIP code |
| Postal Code: | 17225 |
| Area Code: | 717 |
| Blank Name: | GNIS feature ID |
| Blank Info: | 1191484 |
Williamson is an unincorporated community in St. Thomas Township in Franklin County, Pennsylvania, United States. Williamson is located along Pennsylvania Route 995, northwest of Greencastle and southwest of Chambersburg.[1]
Williamson was platted circa 1870 by land owner Samuel Z. Hawbaker,[2] and may be named after Hugh Williamson, the patriot contemporary of Benjamin Franklin, both whom were Founding Fathers of the United States. Another possibility is that the community is named after an unknown local denizen surnamed Williamson, perhaps an early postmaster of the local post office that has been in operation at Williamson since 1872.[3]