{"nrhp_refnum":"11000246","name":"Ziock Building","other_names":["Tower Building","Amerock Building"],"category":"building","location":{"address":"416 S. Main St.","address_restricted":false,"city":"Rockford","county":"Winnebago County","state":"IL","lat":42.26967250300004,"lon":-89.09691282299997,"geom_source":"nps_gis"},"listed_date":"2011-05-04","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Industry","Architecture"],"significance_levels":["local"],"summary":{"what_it_is":"A reinforced concrete industrial loft (Daylight Factory) at 416 South Main Street in Rockford, Illinois, just south of downtown on the Rock River. It was built in three phases: 1912-1913, 1919-1920 and 1950.","why_significant":"The building was commissioned by William Ziock Jr., a key figure in Rockford's knitting industry, and was the tallest building in Rockford when finished in 1913 and again after its 13-story addition. It is an example of flat slab reinforced concrete construction and ties together the city's knitting and hardware manufacturing industries. It remains an icon of Rockford industry and its skyline.","narrative":"Rising along the west bank of the Rock River just south of downtown Rockford, this reinforced concrete factory at 416 South Main Street grew in three stages. William Ziock Jr., a leading figure in the city's knitting industry, commissioned the first eleven-story section, completed in 1913, when it was the tallest building in Rockford. A thirteen-story addition followed in 1919-1920, built by the Holm-Page Company, and the American Cabinet Hardware Company added a six-story wing in 1950. The structure uses flat slab construction, with flared concrete columns supporting floors that carry curtain walls and wide steel-sash windows, a form often called a Daylight Factory. Its open floors hosted knitting, paper box production and later hardware manufacturing, and also held civic events such as a 1921 car show. The building is vacant today, with boarded entries and many damaged windows, yet it keeps its original construction, massing and presence on the Rockford skyline as a symbol of the city's industrial past.","period_of_significance":null,"architect_builder":"Unknown Chicago architect; Majestic Construction Company (1912-13); Holm-Page Company (1919); Sjostrom and Sons (1950)","architectural_style":"Other: Industrial Loft/Daylight Factory","criteria":[],"status_note":"Vacant and without electrical service; entries are boarded up; many windows have missing or broken panes, though the building retains integrity.","vacant_flag":true,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:55:37.275465-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/21/8944/28894421/content/electronic-records/rg-079/NPS_IL/11000246.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/11000246/3c4feaa4de-800.webp","url_1600":"https://nationalhistoricalregister.com/media/11000246/3c4feaa4de-1600.webp","licence":"CC BY-SA 3.0","author":"Teemu08","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Ziock_Building.JPG\" rel=\"noopener\">Teemu08</a>, <a href=\"https://creativecommons.org/licenses/by-sa/3.0\" rel=\"license noopener\">CC BY-SA 3.0</a>, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Ziock_Building.JPG"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/28894421","wikipedia":"https://en.wikipedia.org/wiki/Ziock_Building","wikidata":"https://www.wikidata.org/wiki/Q16904569"},"indexable":true,"url":"https://nationalhistoricalregister.com/illinois/winnebago-county/ziock-building-11000246/"}