{"nrhp_refnum":"99000115","name":"Route 66, Cayuga to Chenoa","other_names":[],"category":"structure","location":{"address":"Rte 66, bet just N of Township Rd 2200 N and just S of Township Rd 3000 N.","address_restricted":false,"city":"Pontiac","county":"Livingston County","state":"IL","lat":40.75350782700008,"lon":-88.71864879399999,"geom_source":"nps_gis"},"listed_date":"2003-07-23","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Engineering","Transportation"],"significance_levels":["state"],"summary":{"what_it_is":"An 18.2-mile segment of historic Route 66 between Cayuga and Chenoa in Livingston and McLean Counties, Illinois, built as a four-lane divided concrete highway in 1943-44 (southbound) and 1954-55 (northbound). It includes bridges and a box culvert and is owned by the Illinois Department of Transportation.","why_significant":"The segment is significant statewide under Criterion A for transportation, through its association with Route 66 as a major route from Chicago to Santa Monica. It also meets Criterion C for engineering as a representative limited-access four-lane highway built to 1940s and 1950s design standards. It qualifies despite being under fifty years old because of its connection to the famous highway.","narrative":"This 18.2-mile stretch of Route 66 runs from near Cayuga to Chenoa through Livingston and McLean Counties, Illinois. Wartime pavement failure and heavy truck traffic led the state to build new 24-foot-wide, 10-inch-thick concrete lanes beside the original 1920s road. The southbound lanes were built in 1943-44 and the northbound lanes followed in 1954-55 over the 1926 alignment, creating a divided four-lane highway with a grass median. The segment includes six contributing bridges, a concrete box culvert, and six later replacement bridges that do not contribute. Parts of the southbound lanes are now closed to traffic. The road is significant for its link to the national Route 66 corridor between Chicago and California and as an example of limited-access highway engineering from the 1940s and 1950s. It is owned and maintained by the Illinois Department of Transportation.","period_of_significance":"1943-1956","architect_builder":"Unknown","architectural_style":"Other: Limited Access Four-Lane Highway","criteria":["A","C"],"status_note":"Portions of the southbound lanes are abandoned and closed to traffic with dirt mounds and signs; the northbound lanes and part of the southbound lanes near Pontiac remain open with a macadam overlay. Six of the twelve bridges have been replaced.","vacant_flag":null,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:55:37.386294-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/33/8913/28891333/content/electronic-records/rg-079/NPS_IL/99000115.pdf"},"photo":null,"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/28891333","wikipedia":null,"wikidata":null},"indexable":true,"url":"https://nationalhistoricalregister.com/illinois/livingston-county/route-66-cayuga-to-chenoa-99000115/"}