Logan Run (also known as Logan's Run) is a tributary of the Susquehanna River in Northumberland County, Pennsylvania, in the United States. It is approximately 5.7 miles (9.2 km) long and flows through Rush Township. The watershed of the stream has an area of 8.70 square miles (22.5 km2) and is in the Lower Susquehanna River drainage basin. The stream is crossed by five bridges and was home to a gristmill and sawmill at some point in the past. It is considered to be a coldwater fishery and a migratory fishery. Rock of the Catskill Formation, the Pocono Formation, and the Hamilton Formation are present in the watershed.