{"nrhp_refnum":"78001117","name":"Old Stone Arch Bridge","other_names":[],"category":"structure","location":{"address":"E of Clark Center off U.S. 40","address_restricted":false,"city":"Clark Center","county":"Clark County","state":"IL","lat":39.37023949500008,"lon":-87.75808467699994,"geom_source":"nps_gis"},"listed_date":"1978-11-28","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Engineering","Transportation"],"significance_levels":["state"],"summary":{"what_it_is":"A limestone arch bridge less than one acre in size, east of Clark Center in Clark County, Illinois, built between 1828 and 1837 to carry the Old National Road over a waterway.","why_significant":"The nomination argues it is significant for its longevity and continuous use, and as an excellent example of competent engineering and the reliability of masonry arch construction. It was built as part of the National Road by the Army Engineers and remained in use until the road was relocated in 1933. It is one of the few remaining vestiges of the original road construction.","narrative":"Carrying the old National Road over a small waterway east of Clark Center, Illinois, this limestone arch bridge has a span of 17.8 feet, a height of 8.9 feet and a length of 81½ feet. Its gray stones have a smooth exterior face and were set without mortar bond, with keys cut into them to prevent slippage. The stone was quarried in Indiana, floated down the Wabash River on a raft and hauled to the site by ox cart. Army Engineers built it between 1828 and 1837 as part of the road that ran from Cumberland, Maryland toward St. Louis. The bridge served traffic continuously until the road was relocated in 1933. Its builder is unknown. It is described as being in nearly original condition, with no noticeable weaknesses, and is now not in use. It was listed for its engineering quality, its long service and its status as one of the few surviving original features of the road in Illinois.","period_of_significance":"Between 1828 and 1837","architect_builder":null,"architectural_style":null,"criteria":[],"status_note":"Not being used presently; appears to be in original condition with little or no maintenance since construction.","vacant_flag":true,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:55:35.735988-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/66/8918/28891866/content/electronic-records/rg-079/NPS_IL/78001117.pdf"},"photo":null,"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/28891866","wikipedia":"https://en.wikipedia.org/wiki/Old_Stone_Arch_Bridge_(Clark_Center,_Illinois)","wikidata":"https://www.wikidata.org/wiki/Q16896161"},"indexable":true,"url":"https://nationalhistoricalregister.com/illinois/clark-county/old-stone-arch-bridge-78001117/"}