{"nrhp_refnum":"75001621","name":"Trenton City/Calhoun Street Bridge","other_names":["Calhoun Street Bridge"],"category":"structure","location":{"address":"Spans Delaware River between Morrisville, PA and Trenton, NJ","address_restricted":false,"city":"Morrisville","county":"Bucks County","state":"PA","lat":40.219850731000065,"lon":-74.77783519599996,"geom_source":"nps_gis"},"listed_date":"1975-11-20","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Industry","Transportation"],"significance_levels":["national"],"summary":{"what_it_is":"A seven-span Pratt truss roadway bridge carrying traffic across the Delaware River between Trenton, New Jersey, and Morrisville, Pennsylvania. It was completed by 1885 and fabricated by the Phoenix Bridge Company of Phoenixville, Pennsylvania.","why_significant":"The bridge is one of the few surviving long bridges built with Phoenix columns, a type of built-up wrought-iron compression member that was widely used from about 1867 to the late 19th century. The nomination states it is probably the longest Phoenix Bridge and that it remains open to traffic. It is also described as the second oldest bridge on the Delaware River, after Roebling's Lackawaxen Aqueduct.","narrative":"Wrought-iron roadway bridge crossing the Delaware River between Trenton, New Jersey, and Morrisville, Pennsylvania, completed by 1885. Its 1,280-foot length is divided into seven Pratt truss spans of nine panels each, with trusses 26 feet deep. The compression members are Phoenix columns, round members made of four rolled semicircular sections riveted together. Samuel Reeves of the Phoenix Iron Works patented the design after Wendel Bollman, an engineer for the Baltimore and Ohio Railroad, worked on a similar hollow column. The superstructure was fabricated by the Phoenix Bridge Company of Phoenixville, Pennsylvania. The abutments and piers are rough stone, with cut-block on the upstream ice-breaker edge. It is significant as one of the few surviving long bridges of this type, probably the longest Phoenix bridge, and it is still open to traffic. It is also the second oldest bridge on the Delaware River, after Roebling's Lackawaxen Aqueduct.","period_of_significance":"1885","architect_builder":"Phoenix Bridge Company, Phoenixville, Pennsylvania (superstructure fabricator); Trenton City Bridge Company with F. C. Larvthortp, consulting engineer (erection)","architectural_style":"Pratt truss with Phoenix column","criteria":[],"status_note":"In good condition; the wooden deck has been replaced by a steel lattice and the bridge remains open to traffic.","vacant_flag":false,"machine_generated":true,"model":"claude-haiku-5-5","prompt_version":"v1.1-2026-10-29","generated_at":"2026-10-29 17:11:30.595446-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_PA/75001621.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/75001621/fb0ac27e11-800.webp","url_1600":"https://nationalhistoricalregister.com/media/75001621/fb0ac27e11-1600.webp","licence":"CC BY-SA 3.0","author":"Aerolin55","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Calhoun_Street_Bridge_2.jpg\" rel=\"noopener\">Aerolin55</a>, <a href=\"https://creativecommons.org/licenses/by-sa/3.0\" rel=\"license noopener\">CC BY-SA 3.0</a>, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Calhoun_Street_Bridge_2.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/71996628","wikipedia":"https://en.wikipedia.org/wiki/Calhoun_Street_Bridge","wikidata":"https://www.wikidata.org/wiki/Q5019790"},"indexable":true,"url":"https://nationalhistoricalregister.com/pennsylvania/bucks-county/trenton-city-calhoun-street-bridge-75001621/"}