Juniata Bridge Crossing Juniata River Duncannon Pennsylvania
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BH Photo #359926
Most probably this bridge was replaced by the concrete arch bridge at the mouth of the Juniata River on what is now PA-849 (Newport Road) but was once US-15. The concrete arch bridge was built in 1922, your bridge probably preceded it in the same location. Info at Historicbridges org.
The location of the pin on those abandoned piers in the river are also significant. They supported a wooden, through truss, covered aqueduct which carried the main line of the Pennsylvania Canal from Duncan's Island (at a small crossroads called Amity Hall) to the south bank of the Juniata River. I would have to dig up some old books to find further information. I hiked back to the north abutment about forty or more years ago, before PennDot blocked it off.