Pennsylvania Route 166
| Route information | ||||
|---|---|---|---|---|
| Maintained by PennDOT | ||||
| Length | 21.9 mi (35.2 km) | |||
| Major junctions | ||||
| South end | US 119 in Point Marion | |||
| PA 21 in Masontown | ||||
| North end | US 40 in Redstone Township | |||
| Location | ||||
| Country | United States | |||
| State | Pennsylvania | |||
| Counties | Fayette | |||
| Highway system | ||||
| ||||
Pennsylvania Route 166 (PA 166) is a north–south state highway in Fayette County, Pennsylvania. It follows the path of the Monongahela River along the entire western border of Fayette County.