| Smiley Run | |
| Name Other: | Tributary to Youghiogheny River |
| Map Size: | 300 |
| Pushpin Map: | USA Pennsylvania#USA |
| Pushpin Map Size: | 300 |
| Pushpin Map Caption: | Location of Smiley Run mouth |
| Pushpin Map Alt: | Map of Smiley Run mouth location |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | State |
| Subdivision Name2: | Pennsylvania |
| Subdivision Type3: | County |
| Subdivision Name3: | Fayette |
| Subdivision Type4: | Borough |
| Subdivision Name4: | Dawson |
| Length: | 2.8miles[1] |
| Discharge1 Location: | Youghiogheny River |
| Discharge1 Avg: | 3.73cuft/s at mouth with Youghiogheny River[2] |
| Source1: | Jacobs Creek divide |
| Source1 Location: | about 1 mile south of Chaintown, Pennsylvania[3] |
| Source1 Coordinates: | 40.0869°N -79.6594°W[4] |
| Source1 Elevation: | 1220feet |
| Mouth: | Youghiogheny River |
| Mouth Location: | Dawson, Pennsylvania[5] |
| Mouth Coordinates: | 40.0503°N -79.665°W |
| Mouth Elevation: | 843feet |
| Progression: | generally south |
| River System: | Monongahela River |
| Tributaries Left: | unnamed tributaries |
| Tributaries Right: | unnamed tributaries |
| Bridges: | Gillespie Road, Davis Road, Banning Road, Rimel Road, School Road |
Smiley Run is a 2.8miles long 2nd order tributary to the Youghiogheny River in Fayette County, Pennsylvania.
Smiley Run rises about 1 mile south of Chaintown, Pennsylvania,[3] and then flows south to join the Youghiogheny River at Dawson.[5]
Smiley Run drains of area, receives about 42.1 in/year of precipitation, has a wetness index of 344.85, and is about 44% forested.[2]