| Bilger Run | |
| Name Other: | Tributary to Kratzer Run |
| Image Alt: | Bilger's Rocks showing rock outcrop and snow |
| Map Size: | 300 |
| Pushpin Map: | USA Pennsylvania#USA |
| Pushpin Map Size: | 300 |
| Pushpin Map Caption: | Location of Bilger Run mouth |
| Pushpin Map Alt: | Map of Bilger Run mouth location |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | State |
| Subdivision Name2: | Pennsylvania |
| Subdivision Type3: | County |
| Subdivision Name3: | Clearfield |
| Length: | 5.05miles[1] |
| Discharge1 Location: | Kratzer Run |
| Discharge1 Avg: | 7.22cuft/s at mouth with Kratzer Run[2] |
| Source1: | Bell Run divide |
| Source1 Location: | about 2 miles southeast of Chestnut Grove, Pennsylvania |
| Source1 Coordinates: | 41.0042°N -78.6336°W[3] |
| Source1 Elevation: | 1710feet[4] |
| Mouth Location: | about 0.25 miles northeast of Stronach, Pennsylvania |
| Mouth Coordinates: | 40.9722°N -78.5697°W |
| Mouth Elevation: | 1309feet[5] |
| Progression: | Kratzer Run → Anderson Creek → West Branch Susquehanna River → Susquehanna River → Chesapeake Bay → Atlantic Ocean |
| River System: | Susquehanna River |
| Tributaries Left: | Hughey Run |
| Tributaries Right: | Fenton Run |
| Bridges: | Evergreen Road, Bilgers Rocks Road, PA 879 |
Bilger Run is a 5.05miles long 2nd order tributary to Kratzer Run in Clearfield County, Pennsylvania and Kratzer Run's largest and only named tributary. Its watershed accounts for nearly half of the greater Kratzer Run watershed.[6] This is the only stream of this name in the United States.[3] Bilger Run has an ID number of 1169617 from the US Board of Geographic Names.[3]
Bilger Run rises about 2 miles southeast of Chestnut Grove, Pennsylvania, in an area of wetlands and then flows generally southeast to join Kratzer Run at Stronach. It runs through areas that have been surfaced mined for coal in its upper reaches.[5]
Bilger Run drains of area, receives about 43.9 in/year of precipitation, has a wetness index of 407.40, and is about 68% forested.[2] Bilger Run is heavily loaded with metals from Acid Mine Drainage (AMD) and contributes a lot to the pollution load of Kratzer Run and then on into Anderson Creek. No fish were found at the sampling station on Bilger Run.[7]
Bilger Run drains parts of the Anderson Creek Montgomery Creek LCA and is also the location of Bilger Rocks BDA. The LCA is noted for providing contiguous forested habitat for interior forest species, while the BDA provides habitat for a species of rare plant.[8]