Edgerton is a city in Rock County and partly in Dane County in the U.S. state of Wisconsin. The population was 5,945 at the 2020 census. Of this, 5,799 were in Rock County, and 146 were in Dane County. Known locally as "Tobacco City U.S.A.," because of the importance of tobacco growing in the region, Edgerton continues to be a center for the declining tobacco industry in the area.

Rock County is a county in the U.S. state of Wisconsin. As of the 2020 census, the population was 163,687. Its county seat is Janesville. Rock County comprises the Janesville-Beloit, WI Metropolitan Statistical Area and is included in the Madison-Janesville-Beloit, WI Combined Statistical Area.