May 1843
Benjamin Brown joined the Congregational church in Beloit.
BeloitGrade A · 1 independent source
The evidence
“lived here until her death, in 1899, at the age of ninety-two years.) The corner stone for their first building, "the old stone church," was laid at the northwest corner of Broad and Prospect streets, July 6, 1842, and the completed building was dedicated January 3, 1844. In May, 1843, Benjamin Brown joined that church, where his wife was already a member, and in 1845 their infant son, "William Fiske (the editor of this county history) was baptized there by the Rev. Mr. Clary. There also, December 25, 1843, had occurred the funeral services of Dr. Horace White, leader of the New England colony.”
1908-brown-rock-county/13-beloit-churches.md, Vol. 1, PDF p. 288 / book p. 264
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