Walworth County is a county located in the U.S. state of Wisconsin. As of the 2010 census, the population was 102,228. Its county seat is Elkhorn. The county was created in 1836 from Wisconsin Territory and organized in 1839. It is named for Reuben H. Walworth. Walworth County comprises the Whitewater-Elkhorn, WI Micropolitan Statistical Area and is included in the Milwaukee-Racine-Waukesha, WI Combined Statistical Area. Lake Geneva, the University of Wisconsin-Whitewater, and Alpine Valley Resort, and Music Theatre are located in Walworth County.

The Delevan National Wildlife Refuge is one of six refuges in the Sacramento National Wildlife Refuge Complex in the Sacramento Valley of central northern California.

McHenry County is a county located in the U.S. state of Illinois. According to the 2020 Census, it had a population of 310,229, making it the sixth-most populous county in Illinois. Its county seat is Woodstock. McHenry County is one of the five collar counties of the Chicago-Naperville-Elgin, IL-IN-WI Metropolitan Statistical Area. Long known as a center of recreation along with agriculture in the western portion, it has more recently experienced rapid rates of suburbanization, exurbanization and urbanization, but the western portions of the county remain primarily agricultural and rural.

Whitewater is a city located in Walworth and Jefferson counties in the U.S. state of Wisconsin. Located near the southern portion of the Kettle Moraine State Forest, Whitewater is the home of the University of Wisconsin–Whitewater. As of the 2010 census, the city's population was 14,390, which includes 11,150 in Walworth County and 3,240 in Jefferson County.