The Wisconsin legislature approved an act declaring Rock County to be the Seventeenth Senatorial District and establishing six Assembly Districts.

The evidence

• “Met in extra session September 10 and adjourned September 26. By an act approved April 11, 1861, Rock County was declared to be the Seventeenth Senatorial District, and six Assembly Districts were established, viz. : The towns of Center, Janesville. Magnolia, Porter and Union, one ; the towns of Fulton, Harmony, Lima and Milton, one ; the towns of Bradford, Clinton, Johnstown and La Prairie, one ; the towns of Beloit and Turtle and the city of Beloit, one ; the city of JanesvillCj one, and the towns of Avon, Newark, Rock, Plymouth and Spring Valley, one.] Senate — Ezra A.”

  1879-history-of-rock-county/10-rock-county-ch04-early-maps-courts-railroads.md, PDF p. 372 / book p. 376

  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