Wisconsin's 2nd congressional district is a congressional district of the United States House of Representatives in southern Wisconsin, covering Dane County, Iowa County, Lafayette County, Sauk County and Green County, as well as portions of Richland County and Rock County. The district includes Madison, the state's capital, its suburbs and some of the surrounding areas. Like many districts anchored by a college town, the district is heavily Democratic, and includes the University of Wisconsin-Madison.

Dane County is a county in the U.S. state of Wisconsin. As of the 2020 census, the population was 561,504, making it the second-most populous county in Wisconsin after Milwaukee County. The county seat is Madison, which is also the state capital.