Industrial History: 1833-1901 US-22 Clarks Ferry Bridge over Susquehanna near Duncannon, PA, was Longest Covered Bridge

Wednesday, February 11, 2026

1833-1901 US-22 Clarks Ferry Bridge over Susquehanna near Duncannon, PA, was Longest Covered Bridge

1833: (Archived Bridge Hunter; Bridge Hunter)

Metrotrails posted

Historic image of the Clarks Ferry Covered Bridge, over the Susquehanna near Duncannon PA.

The bridge originally had a towpath walkway on the outside for mules to tow canal boats over the river in slack water provided by a 1,998 foot long dam, the remnants of which can be seen today.

The Eastern Division Canal that used this bridge was completed in 1833 and abandoned about 1901.

The Clark's Ferry Bridge was part of the Main Line Pennsylvania Canal built in 1828. Mules walked on a cantilevered walkway outside the structure and towed canal boats across the river. The dam below the bridge was known as Green's Dam and created a calm surface for the canal boats. The bridge put an end to the hand-poled ferry that existed at this location for nearly 50 years.
Seven different bridges have crossed the Susquehanna at this location. While in Dauphin County the bridge has always had a strong connection to Duncannon and contributed greatly to its growth in the mid-1800s. The covered bridge that stood in the distance was considered at the time to be the longest covered bridge in the world at 2088 feet [636m].
[ArchivedBridgeHunter_1833]

BridgeHunter_1833
"On the towpath on the down-stream side of the bridge can be seen a horse team towing a boat out of the Duncan's Island outlet lock."

BridgeHunter_1833

I noticed what looked like the remnants of the bridge piers and the dam on a satellite image. So I fired up Google Earth to look for images where the Susquehanna had a low flow. These are three of the images I found. It is interesting how some flows emphasize the piers whereas others highlight the dam.