Historic Bridge Survey

Pennsylvania is home to thousands of bridges, many of them historically significant. Maintaining the safety and capacity of the Commonwealth's bridge network, while preserving and protecting our legacy of historic bridges, is one of our most important goals.

As part of our efforts to manage and protect our historic bridges, PennDOT, in cooperation with the Federal Highway Administration and the Pennsylvania Historical and Museum Commission, has undertaken the monumental task of compiling an inventory of all state and locally owned bridges that are greater than 20 feet in length and constructed prior to 1957. An early effort to survey historic bridges began in the 1980s, but was limited to state owned bridges. 

In 1996, PennDOT contracted with A.G. Lichtenstein and Associates, Inc., to evaluate each of the approximately 12,000 bridges, both individually and thematically, for their potential eligibility to the National Register of Historic Places. The ultimate goal of this project, is the creation of a Bridge Management Plan that will identify which bridges can and should be preserved.


The inventory project survey work was divided into three different phases. First, in order to have the tools and framework needed to evaluate the significance of the bridges, the development of a detailed transportation and engineering context was necessary prior to any evaluations. In addition, information on major construction and engineering styles, as well as builders, materials, and workmanship was also gathered. 

Next, using this context, as well as and historical and management data maintained by the Department, an initial evaluation of all bridges was completed, resulting in the determination that some 9,000 bridges were ineligible for listing on the National Register of Historic Places.

 Finally, the roughly 3,000 remaining bridges were selected for field views to further assess their eligibility and integrity. The findings of those selected bridge evaluations were reviewed by an expert panel selected by the Department, PHMC, and the Federal Highway Administration, and final determinations of National Register eligibility for the bridges were made. We are still in the process of determining which bridges might be contributing properties to National Register Historic Districts that surround them or are nearby.


Through this inventory, more than 12,000 of Pennsylvania's state, county, railroad-related, and highway bridges have been evaluated for National Register eligibility. Of this number approximately 597 were recommended as eligible, and roughly 100 bridges were already listed on the National Register.

Preliminary survey results have been distributed to all PennDOT Engineering Districts and other interested parties for planning purposes. The database serves as guidance for district cultural resources professionals who can research the context, significance, and eligibility status of all historic bridges in their regions. The results of their research is then incorporated into the overall environmental and project planning for new highway projects and improvements. A Microsoft Access database that summarizes the results of the bridge survey is now available on our Publications page for researchers and the general public, as a permanent and dynamic record of Pennsylvania's historic links to the past.

For more information

Kara Russell
Architectural Historian
PennDOT Bureau of Environmental Quality
PO Box 3790
Harrisburg, PA 17105-3790
(717) 705-1484