{"nrhp_refnum":"70000510","name":"Montgomery County Courthouse","other_names":["Old Courthouse"],"category":"building","location":{"address":"NW corner 3rd and Main Sts.","address_restricted":false,"city":"Dayton","county":"Montgomery County","state":"OH","lat":39.759417631000076,"lon":-84.19232887399994,"geom_source":"nps_gis"},"listed_date":"1970-01-26","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Politics/Government","Architecture"],"significance_levels":["national"],"summary":{"what_it_is":"The Old Court House is a Greek Revival limestone courthouse at the northwest corner of Third and Main Streets in Dayton, Ohio, built between 1847 and 1850.","why_significant":"The nomination argues it is one of the finest remaining examples of Greek Revival architecture in the United States, noted for its simple form and the unusual curved wall treatment at the rear corners. It also has fortress-like security features and a flying staircase. Abraham Lincoln spoke from its steps in 1859, and it serves as the symbol of the Dayton community.","narrative":"Dayton's Old Court House, at Third and Main Streets, is a Greek Revival courthouse built from 1847 to 1850 of native limestone known as \"Dayton Marble.\" Its six-column portico follows a quasi-Ionic order and somewhat resembles the Theseum of Athens. At the rear corners, the colonnade is replaced by a single column with the wall curved around it, giving each side the look of a portico at both ends; the nomination says noted architects found this treatment on no other American building. Inside are a flying staircase and two smaller spiral staircases. Solid iron front doors and inward-swinging shutters with iron bar latches reflect the unrest of the period. Abraham Lincoln spoke from its steps on September 17, 1859. The exterior is little altered apart from a tin-covered stone slab roof, and the interior has seen only modest changes. Local residents regard the building as a symbol of the Dayton community.","period_of_significance":"1847-1850","architect_builder":null,"architectural_style":"Greek Revival (quasi-Ionic order, hexastyle portico)","criteria":[],"status_note":"Condition listed as excellent and occupied for government use; plans were in preparation to convert it to a county historical museum.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:53:09.048835-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_OH/70000510.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/70000510/578520596c-800.webp","url_1600":"https://nationalhistoricalregister.com/media/70000510/578520596c-1600.webp","licence":"CC BY-SA 4.0","author":"Steve Morgan","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Old_Montgomery_County_Courthouse_-_Dayton,_Ohio_(2021).jpg\" rel=\"noopener\">Steve Morgan</a>, <a href=\"https://creativecommons.org/licenses/by-sa/4.0\" rel=\"license noopener\">CC BY-SA 4.0</a>, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Old_Montgomery_County_Courthouse_-_Dayton,_Ohio_(2021).jpg"},"district":{"nrhp_refnum":"100004316","name":"Downtown Dayton Historic District","url":"https://nationalhistoricalregister.com/districts/ohio/downtown-dayton-historic-district-100004316/"},"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/71990551","wikipedia":"https://en.wikipedia.org/wiki/Montgomery_County_Courthouse_(Ohio)","wikidata":"https://www.wikidata.org/wiki/Q6905692"},"indexable":true,"url":"https://nationalhistoricalregister.com/ohio/montgomery-county/montgomery-county-courthouse-70000510/"}