The Portsmouth Bridge (also known as the Pile Bridge) was a wooden trestle bridge that carried both highway and railroad traffic across the Piscataqua River from Noble’s Island to Kittery, Maine, in the vicinity of the old/new Sarah Mildred Long Bridge.

The Portsmouth Bridge from a Davis Brothers stereocard, c. 1870-1885 (PS1633.33).

According to the Portsmouth Herald, on Saturday, March 16, 1918, the Portsmouth Bridge was badly racked by ice.  Upriver, the ice had already carried away 350 feet of the Dover Point Bridge, which had somehow passed by the Portsmouth Bridge and was against the pilings of the second bridge to New Castle creating concerns that bridge might collapse.
Every precaution was made to keep the Portsmouth Bridge from being destroyed by the mid-March thaw. On Friday, the naval tug Penacook went upriver to break up as much ice as possible. Early Saturday morning, in addition to the Penacook, two more tugs went upriver to break up ice in and around Little Bay and the Cocheco and Salmon Falls rivers. With each ebb tide, anxiety was high that the bridge would be wiped out completely. A large working force was maintained on the bridge to make any necessary repairs to stabilize it. 

A man attempting to clear ice from the Portsmouth Bridge. Dated to the 1917-1918 winter, the image was most likely taken during this March 1918 effort to save the bridge (P49_154_04, Rice Public Library Collection).

On Friday, the morning trains went across the railroad bridge, but with the afternoon ebb tide, train service was suspended. This caused considerable commuter problems for those employed at the Portsmouth Naval Shipyard. The highway bridge was more heavily damaged and only foot traffic was allowed across the bridge in the morning. In the end, the Portsmouth Bridge held up, and the ice damage was repaired; however, five years later in 1921, the highway bridge was permanently closed. The railroad bridge was in operation until it collapsed under the weight of a train in 1939. Prior to the construction of the new Sarah Mildred Long Bridge, the pilings for the old Portsmouth Bridge could still be seen along the river’s edge.