1850
The Rock County Agricultural Society and Mechanics' Institute was organized, with Mr. Willard elected President.
Rock CountyGrade A · 1 independent source
The evidence
“Mr. Willard came to Wisconsin in 1846, and located some two miles below Janesville, on the east side of Rock River, where he purchased three hundred and forty acres of wild land, upon which he made practical demonstrations of his theories of agriculture. ' As early as 1850, though the country was then quite new, he succeeded by unwearied and continued efforts, in organizing the Rock County "Agricultural Society and Mechanics' Institute," of which he was elected President ; and by liberal contributions of both time and money he succeeded, beyond the expectations of its most sanguine friends, in placing the Society on a permanent basis. Before this Society, in 1853, he, as its President, delivered an able address, which was published in the " Volume of Transactions of the Wisconsin Agricultural Society" for that year.”
1879-history-of-rock-county/11-rock-county-ch05-press-institutions-tragedy.md, PDF p. 437 / book p. 441
Butterfield, C. W., et al. The History of Rock County, Wisconsin: its early settlement, growth, development, resources, etc. Chicago: Western Historical Company, 1879. Cornell University Library via the Internet Archive, archive.org/details/cu31924028871585.
Grade A: Found on a page of one of our sources