July 1839
Merritt Bostwick, of New York, settled in Beloit.
BeloitGrade A · 1 independent source
The evidence
“Swingle, Pennsylvania, Turtle, September, 1838; Merritt Bostwick, New York, Beloit, July, 1839; Russell Harvey, Connecticut, Turtle, April, 1839; B. F. Murray, New York, Turtle, May, 1839; H. J. Murray, same place, June, 1839; S.”
1908-brown-rock-county/31-smaller-cities-villages-towns.md, Vol. 2, PDF p. 206 / book p. 710
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