{"nrhp_refnum":"99000117","name":"Route 66, Girard to Nilwood","other_names":[],"category":"structure","location":{"address":"Rte 66, between IL 4 S of Girard and IL 4","address_restricted":false,"city":"Nilwood","county":"Macoupin County","state":"IL","lat":39.41945085400005,"lon":-89.78656344183835,"geom_source":"nps_gis"},"listed_date":"2002-05-23","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Engineering","Transportation"],"significance_levels":["state"],"summary":{"what_it_is":"A 4.0-mile segment of early Route 66 in Macoupin County, Illinois, running from Illinois Route 4 south of Girard to Illinois Route 4 in Nilwood. It was built around 1920 as part of State Bond Issue 4 and includes the concrete road, a bridge, a railroad overpass and five culverts.","why_significant":"The segment is significant under Criterion A for transportation, through its link to Route 66 from 1926 to 1931. It is significant under Criterion C for engineering as a representative example of early 1920s Illinois road-building standards. It is described as the longest segment on this stretch that keeps its historic cross-section and original pavement.","narrative":"This four-mile stretch of road between Girard and Nilwood in Macoupin County, Illinois, was built around 1920 as part of State Bond Issue 4 and became part of U.S. Route 66 when the highway was designated in 1926. It carried Route 66 traffic until the route was realigned east of Springfield in 1930-1931. The original sixteen-foot concrete pavement survives, with four-foot gravel shoulders, five concrete box culverts, a 1920 reinforced concrete bridge over Shearles Branch and a 1930 railroad overpass. Its significance rests on two points. It reflects the hard-surfaced road that sped the movement of goods, farm products and coal miners in the area. It also represents the design standards of Illinois road building in the late 1910s and early 1920s. The form calls it the longest segment in the area that keeps its historic cross-section and original pavement, so travelers can still sense 1920s driving conditions.","period_of_significance":"A: 1926-1931; C: 1919-1931","architect_builder":"Unknown","architectural_style":"Other: Concrete Road","criteria":["A","C"],"status_note":"Still in road-related use; owned and maintained by the Illinois Department of Transportation. The original concrete pavement is cracked in places but described as in good shape.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:55:37.213723-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/45/8913/28891345/content/electronic-records/rg-079/NPS_IL/99000117.pdf"},"photo":null,"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/28891345","wikipedia":null,"wikidata":null},"indexable":true,"url":"https://nationalhistoricalregister.com/illinois/macoupin-county/route-66-girard-to-nilwood-99000117/"}