Summer 1842
The central bridge at Beloit (a toll bridge built by a private company, a timber trestle structure framed by John P. Houston) was built over Rock River; it was later given to the village in 1844.
BeloitGrade A · 2 independent sources
The evidence
“The winter was beautiful, with from six to ten inches of snow, but the next was the hard winter, with sleighing from the 9th of November to the 10th of April, 1843, and upon the 11th teams crossed Eock river on the ice. I was lost on Eock prairie November 17, 1842, in a storm with the snow two feet deep, which increased during the winter to four feet on the level, and cattle, horses, hogs and sheep perished with cold and hunger. The central bridge at Beloit had been built in the summer of 1842. In April, 1844, I moved to the west side of the river and built a stone house there, the second residence on the west side, at the northwest corner of Third street and E (now St.”
1908-brown-rock-county/06-history-of-beloit.md, Vol. 1, PDF p. 166 / book p. 150
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
“ckford. The winter was beau- tiful, with from six to ten inches of snow, but the next was the hard winter, with sleighing from the 9th of November to the 10th of April, 1843, and upon the 11th teams crossed Eock river on the ice. I was lost on Eock prairie November 17, 1842, in a storm with the snow two feet deep, which increased during the winter to four feet on the level, and cattle, horses, hogs and sheep perished with cold and hunger. The central bridge at Beloit had been built in the summer of 1842. In April, 1844, I moved to the west side of the river and built a stone house there, the second residence on the west side, at the northwest corner of Third street and E (now St. Lawrence avenue), later owned and occupied by Charles Hanson. From May 10, 1844, rain fell al- most continually for fifty days and in July a steamboat came up the river, going on up to Jefferson. During that spring Ira Mer- sey, John Atchley and myself started”
https://archive.org/stream/rockcountywiscon01brow/rockcountywiscon01brow_djvu.txt
archive.org, https://archive.org/stream/rockcountywiscon01brow/rockcountywiscon01brow_djvu.txt
Grade B: Found on an institutional web page