| County Bridge No. 171 | |
| Coordinates: | 40.0533°N -75.5008°W |
| Built: | 1907 |
| Builder: | P.J. McCormick & Sons |
| Architecture: | Stone arch |
| Added: | June 22, 1988 |
| Area: | less than one acre |
| Refnum: | 88000762 |
County Bridge No. 171 is a historic stone arch bridge located in Tredyffrin Township, Chester County, Pennsylvania. It spans Valley Creek. It has three spans; the main span is 25 feet long and flanked by two 15-feet long spans. The bridge was constructed in 1907, of coursed rubble with brick arch rings and a contrasting parapet.[1]
It was listed on the National Register of Historic Places in 1988.