West Branch Mahantango Creek is a tributary of Mahantango Creek in Snyder County and Juniata County, in Pennsylvania, in the United States. It is approximately 18 miles (29 km) in length.[1] The creek starts on Shade Mountain in Snyder County. It ends at its confluence with Mahantango Creek. Most of the land in the watershed is devoted to forest or agriculture. Trout and minnows have been observed in the creek, which is stocked with trout. A covered bridge was built over it in 1908.