Muddy Run is a tributary of the West Branch Susquehanna River in Northumberland County, Pennsylvania, in the United States. It is in length. The creek is several miles northeast of the community of Milton. Main land uses include agricultural land and forest. The area of the creek's watershed is , most of which is agricultural land. Muddy Run is entirely within Turbot Township. Most of the rock in the watershed is shale. The most common soil series is the Berks-Weikert-Bedington series. Course Muddy Run begins in a valley in eastern Turbot Township, near the Paradise Church. The creek heads westward before turning south and then southwest. It crosses under Interstate 80 and turns due west again. After some distance, the creek crosses under Pennsylvania Route 147 and turns northwest past a country club. North of the country club, it turns abruptly north and then west again, crossing under Pennsylvania Route 405 and entering the West Branch Susquehanna River. Tributaries Muddy Run's main tributaries are unnamed. Hydrology The Hoeganaes Corporation, in the northwestern part of the watershed, is the only entity permitted to discharge sediment in the Muddy Run watershed. There is a total daily load of of sediment. comes from cropland, comes from the banks of streams, and comes from land used for hay or pastures. A total of comes from developed land, comes from forests, and comes from wetlands. The average annual amount of precipitation between the early 1990s and the early 2010s was . The average amount of annual runoff during the same time period was . Geology In the Muddy Run watershed, 90% of the rock is shale from the Bloomsburg/Mifflinburg Formation Undivided and the Wills Creek Formation. The remaining 10% is composed of siltstone and limestone from the Keyser/Tonoloway Formation Undivided. Most of the western part of the watershed is on the Bloomsburg/Mifflinburg Formation Undivided, with the exception of a band in the central-western part of the watershed, which is on the Wills Creek Formation. The Keyser/Tonoloway Formation Undivided occurs in an area in the northeastern part of the watershed. The rest of the watershed is on the Wills Creek Formation. The main soil series in the Muddy Run watershed is the Berks-Weikert-Bedington, which is a silt-loam with shale. Other soil types in the watershed include the Chenango-Pope-Holly series, the Hagerstown-Edom-Washington series, and the Leck Kill-Meckesville-Calvin series. The Berks-Weikert-Bedington series occurs in the central and northwestern