Dauphin County Bridge No. 27
 Dauphin County Bridge No. 27 also known as Seaman Bridge is a historic iron truss bridge spanning Mahantango Creek at Mifflin Township Dauphin County Pennsylvania and Lower Mahanoy Township Northumberland County Pennsylvania. It has a single span 162.5-foot-long (49.5 m). The bridge was constructed in 1896 by the Chambersburg Bridge Company Chambersburg Pennsylvania. The bridge was closed to vehicular traffic in 1978.It was added to the National Register of Historic Places in 1993.