{"nrhp_refnum":"74001786","name":"Martin's Mill Covered Bridge","other_names":[],"category":"structure","location":{"address":"SW of Greencastle over Conococheague Creek","address_restricted":false,"city":"Greencastle","county":"Franklin County","state":"PA","lat":39.76498845400005,"lon":-77.77568788799994,"geom_source":"nps_gis"},"listed_date":"1974-02-15","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Transportation"],"significance_levels":["state"],"summary":{"what_it_is":"A lattice-type covered bridge in Greencastle, Franklin County, Pennsylvania, spanning the stream at the site of an earlier grist and saw mill. The document describes it as the longest lattice-type covered bridge in Pennsylvania.","why_significant":"The nomination argues the bridge is significant as the longest lattice covered bridge in the Commonwealth and as an example of a vanishing bridge type, despite alterations from destruction and restoration. It also cites its role as a long-used east-west link between Antrim and Montgomery Townships, and the local preservation effort that saved it from demolition.","narrative":"Spanning a stream in Franklin County, Pennsylvania, this lattice-type covered bridge occupies the site of an early grist and saw mill, with settlement in the area dating to the 1730s or early 1740s. Citizens petitioned the county court in January 1849 for a bridge at the mill crossing, and the board of viewers agreed it was needed and cheaper to build on that site than at the original ford. The bridge served as an approach to the mills and an east-west link between Antrim and Montgomery Townships. Repairs followed flood damage in 1936 and a truck collapse in 1948. In 1958 the county voted to demolish it, but after a court fight and a 1962 transfer to a non-profit association, it was rebuilt following Hurricane Agnes. It is regarded as the longest lattice-type covered bridge in Pennsylvania and a surviving example of a bridge type that was largely lost in the 1972 floods.","period_of_significance":"1849","architect_builder":null,"architectural_style":null,"criteria":[],"status_note":"Reconstructed after damage from Hurricane Agnes and reopened to passenger traffic under a three ton weight limit.","vacant_flag":false,"machine_generated":true,"model":"claude-haiku-5-5","prompt_version":"v1.1-2026-10-29","generated_at":"2026-10-29 17:11:30.194582-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_PA/74001786.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/74001786/ed2acc3eed-800.webp","url_1600":"https://nationalhistoricalregister.com/media/74001786/ed2acc3eed-1600.webp","licence":"CC BY-SA 3.0","author":"JERRYE &amp; ROY KLOTZ MD","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:MARTIN%27S_MILL_BRIDGE.jpg\" rel=\"noopener\">JERRYE &amp;amp; ROY KLOTZ MD</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:MARTIN%27S_MILL_BRIDGE.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/71995174","wikipedia":"https://en.wikipedia.org/wiki/Martin%27s_Mill_Covered_Bridge_(Antrim_Township,_Franklin_County,_Pennsylvania)","wikidata":"https://www.wikidata.org/wiki/Q15249032"},"indexable":true,"url":"https://nationalhistoricalregister.com/pennsylvania/franklin-county/martins-mill-covered-bridge-74001786/"}