1854
The Bushnell House was completed
The evidence
“Bushnell, at a sacrifice of his own cherished pursuits, yielded to much solicitation and the promptings of public spirit, and in 1853 undertook to build the fine hotel which was completed in 1854, and has since been known as the Bushnell House.”
1856-history-of-rock-county/06-beloit.md, PDF p. 83 / book p. 65
Guernsey, Orrin, and Josiah F. Willard, editors. History of Rock County, and Transactions of the Rock County Agricultural Society and Mechanics' Institute. Janesville, Wis.: William M. Doty & Brother, 1856. Cornell University Library via the Internet Archive, archive.org/details/cu31924028871593.
Grade A: Found on a page of one of our sources
“B. Dunbar during the two years, 1853 and 1854, when the Bushnell House was being built. Then Mr.”
1908-brown-rock-county/06-history-of-beloit.md, Vol. 1, PDF p. 182 / book p. 165
Brown, William Fiske, editor. Rock County, Wisconsin: A New History of Its Cities, Villages, Towns, Citizens and Varied Interests, from the Earliest Times, Up to Date. Chicago: C. F. Cooper & Co., 1908. 2 vols. archive.org/details/rockcountywiscon01brow, archive.org/details/rockcountywiscon02brow.
Grade A: Found on a page of one of our sources