Tenmile Run

Tenmile Run is a tributary of the Susquehanna River in eastern Columbia County, Pennsylvania, in the United States. It is 6.1mi long and is entirely in Mifflin Township. The stream's watershed has an area of 8.24 square miles. The first settlers in the area arrived in the late 1700s and a number of mills have been built on the stream. It is designated as a High-Quality Coldwater Fishery and as Class A Wild Trout Waters.CourseTenmile Run begins in southern Mifflin Township, just north of Nescopeck Mountain. The stream flows west-southwest for several miles in a fairly shallow and narrow valley. It then turns north and enters a much broader valley. Over the next few miles, the stream moves from the eastern edge of the valley to the western edge of the valley, where it crosses Pennsylvania Route 339 and turns west, skirting a hill. After a short distance, it turns north and shortly afterwards enters the Susquehanna River.Tenmile Run joins the Susquehanna River 155.53mi upstream of its mouth.Watershed, geography, and hydrologyThe watershed of Tenmile Run has an area of 8.24 square miles. The elevation of Tenmile Run at its mouth is 463ft above sea level.The census-designated place of Mifflinville is located near Tenmile Run. The stream is in the United States Geological Survey topographic quadrangles of Mifflinville and Shumans. There is a small and asymmetrical divide separating the valley of Tenmile Run from another valley that runs westward along the foot of Nescopeck Mountain. It resembles a kame fan or a head-of-outwash and contains a layer of sand and gravel that is 60m thick.