Sussex is a village in Waukesha County, Wisconsin, United States, about 19 miles (31 km) northwest of Milwaukee and 9 miles (14 km) north of Waukesha. The village is 7.24 square miles (19 km2) at an elevation of 930 feet. The population was 11,487 at the 2020 census. It is part of the Milwaukee metropolitan area.

Waukesha County is a county in the U.S. state of Wisconsin. As of the 2020 United States Census, the population was 406,978, making it the third-most populous county in Wisconsin. Its median income of $88,985 placed it as the only county in Wisconsin on the list of the 100 highest-income counties in the U.S. by median income as of 2020. Its county seat and largest city is Waukesha.