Powdermill Run rises on the Warden Run divide about 3 miles northwest of Hannasville, Pennsylvania in Venango County. Powdermill Run then flows southwest through Crawford County into Mercer County to meet French Creek at Carlton, Pennsylvania.[2]
Watershed
Powdermill Run drains 3.80 square miles (9.8 km2) of area, receives about 43.7 in/year of precipitation, has a topographic wetness index of 426.12, and has an average water temperature of 8.17 °C.[4] The watershed is 39% forested.[4]