Sussex is a village in Waukesha County, Wisconsin, United States. It is approximately 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 10,518 at the 2010 census. It is part of the Milwaukee metropolitan area.