Brookfield, city, Waukesha County, southeastern Wisconsin, on the Fox River; incorporated as a city 1954. Primarily a residential suburb of Milwaukee, the city contains some industry and is home to many corporate office facilities. Tourism is also important to the economy. The community, settled in 1820, grew after the coming of the railroad in 1851. Population 34,035 (1980); 35,184 (1990); 38,649 (2000).