Congress approved an act granting 500,000 acres of land to the state; one passage gives the approval date as September 14, 1841.

The evidence

• “By an act of congress, approved September 4, 1841, there were granted to the state 500,000. acres of land, which were, by act of the territorial legislature of 1849, appropriated to the school fund, and the unsold lands of the Milwaukee and Rock river canal company, amounting to about 140,000 acres, were to be included as a part of the above grant. These lands, and the sixteenth section of each township, make up the whole of the school lands of the state.”

  1879-history-of-rock-county/04-wisconsin-railroads-commerce-health-statistics.md, PDF p. 224 / book p. 228

  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