Ashelman Run is a tributary of Coles Creek in Columbia County, Pennsylvania, in the United States. It is approximately 0.7 miles (1.1 km) long and flows through Sugarloaf Township. The stream's watershed has an area of 0.57 square miles (1.5 km2). The stream is designated as a Coldwater Fishery. It is named after Daniel Ashelman, who lived in the area in the early 1800s. Glacial till and other geological features can be found in the vicinity of the stream. It has one unnamed tributary and there are two lakes in the watershed.