{"nrhp_refnum":"78002080","name":"Observatory Historic District","other_names":["See Also:Cincinnati Observatory Building"],"category":"district","location":{"address":"Observatory Pl. and Ave.","address_restricted":false,"city":"Cincinnati","county":"Hamilton County","state":"OH","lat":39.13809542450005,"lon":-84.42269938180432,"geom_source":"nps_gis"},"listed_date":"1978-09-20","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Science","Architecture"],"significance_levels":["local"],"summary":{"what_it_is":"A small historic district in Cincinnati, Hamilton County, Ohio, made up of two observatory buildings and nine Victorian and early 20th-century houses along Observatory Avenue and Observatory Place, built between about 1873 and 1923.","why_significant":"The nomination argues the district is significant architecturally. Most buildings have distinctive detailing, and the two observatory buildings are one-of-a-kind functional designs that serve as the focal point. The houses show a range of styles from about 1874 to 1916. The observatory's history, including its role in astronomy and early weather reporting, is also described.","narrative":"Observatory Historic District in Cincinnati groups eleven buildings around the Cincinnati Observatory, which opened at its Mt. Lookout site in 1873-1875 after the original observatory on Mt. Adams became unsuitable because of city growth and smoke. Next to it stands the small O. M. Mitchel Building, built 1904-1908 to house the original telescope. The surrounding houses on Observatory Avenue and Observatory Place date from about 1874 to 1923 and include a Second Empire house built for director Ormond Stone, an Eastlake-influenced house built for director Jermain G. Porter, and Shingle, Victorian and transitional designs. Many were built for professional and business people on lots platted by John Kilgour. The district was recognized for its architecture: the two observatory buildings are distinctive functional designs, and the houses form a compact streetscape showing how residential styles changed between 1874 and 1916. Seven buildings are treated as pivotal and four as background.","period_of_significance":"1873-1916","architect_builder":"Various; Cincinnati Observatory Building by Samuel Hannaford (per correction); O. M. Mitchel Building by Samuel Hannaford and Sons; Walter I. Farmer House by Willis P. Tharp, remodeled by Garber and Woodward","architectural_style":"Greek Revival observatory buildings; Victorian residences including Second Empire, Eastlake, Shingle and transitional examples","criteria":[],"status_note":"Condition marked excellent. The observatory building houses offices and an astronomical library, the Mitchel Building is used for night educational observations, and the residences are owner occupied.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:53:09.355474-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_OH/78002080.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/78002080/2d5fdd9373-800.webp","url_1600":"https://nationalhistoricalregister.com/media/78002080/2d5fdd9373-1600.webp","licence":"Public domain","author":"Nyttend","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Observatory_Historic_District.jpg\" rel=\"noopener\">Nyttend</a>, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Observatory_Historic_District.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/71989161","wikipedia":"https://en.wikipedia.org/wiki/Observatory_Historic_District","wikidata":"https://www.wikidata.org/wiki/Q7075464"},"indexable":true,"url":"https://nationalhistoricalregister.com/ohio/hamilton-county/observatory-historic-district-78002080/"}