Pewaukee is a city in Waukesha County, Wisconsin, United States. The population was 15,914 at the 2020 census. It is part of the Milwauke…Pewaukee is a city in Waukesha County, Wisconsin, United States. The population was 15,914 at the 2020 census. It is part of the Milwaukee metropolitan area. The name of the city of Pewaukee comes from that of the name of the village, which is rather unclear in itself. Many names have been given as to the etymology of the name. The Village of Pewaukee, which was incorporated out of the town before it incorporated as a city, is surrounded by the city.