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.

Milwaukee County is located in the U.S. state of Wisconsin. At the 2020 census, the population was 939,489, down from 947,735 in 2010. It is both the most populous and most densely populated county in Wisconsin, and the 45th most populous county nationwide; Milwaukee, its eponymous county seat, is also the most populous city in the state. The county was created in 1834 as part of Michigan Territory and organized the following year.