New Berlin is a city in eastern Waukesha County, Wisconsin, United States. The population was 40,451 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.