is a city in Waukesha County, Wisconsin, United States. The population was 38,649 at the 2000 census. Its 2006 estimated population was 39,607. Brookfield is the second largest community in Waukesha County, and the leading commercial suburb of Milwaukee. Formed in the 1950s from the Town of Brookfield, which still survives, the City of Brookfield shares the Elmbrook School District with the Town and with Elm Grove, Wisconsin, although police and fire services are separate for Town and City.
According to the United States Census Bureau, the city has a total area of 27.3 square miles (70.6 km²), of which, 27.2 square miles (70.4 km²) of it is land and 0.1 square miles (0.2 km²) of it (0.26%) is water. The
passes through Brookfield; on the eastern side of this divide, easily marked by the crest at Calhoun Road and Capitol Drive, water flows to Lake Michigan on its way to the Gulf of Saint Lawrence; on the western side of this divide, water flows to the Fox River of Illinois and Wisconsin on its way to the Mississippi River and the Gulf of Mexico.
There is a heron rookery on a site northwest of Capitol Drive and Brookfield Road.