Mahantango Creek, a tributary of the Susquehanna River in Dauphin, Northumberland, and Schuylkill counties, in Pennsylvania
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Mahantango Formation, a mapped bedrock unit in Pennsylvania, New Jersey, New York and Maryland
Little Mahantango Creek joins Mahantango Creek near the village of Rough and Ready.
PA 25 runs parallel to the Mahantongo Mountains and the Mahantango Valley, as well as US 209, for its entire length.