couples living together, 10.80% had a female householder with no husband present, and 35.70% were non-families. 27.10% of households were one person and 10.90% were one person aged 65 or older. The average household size was 2.45 and the average family size was 2.97. Age spread: 23.10% under the age of 18, 15.70% from 18 to 24, 25.20% from 25 to 44, 22.00% from 45 to 64, and 14.00% 65 or older. The median age was 34 years. For every 100 females, there were 92.30 males. For every 100 females age 18 and over, there were 88.80 males. The median household income was $37,266 and the median family income was $47,398. Males had a median income of $33,138 versus $23,394 for females. The per capita income for the county was $18,885. About 7.90% of families and 13.10% of the population were below the poverty line, including 14.40% of those under age 18 and 8.90% of those age 65 or over. Communities Cities Cedar Falls Dunkerton Elk Run Heights Evansdale Gilbertville Hudson Janesville Jesup La Porte City Raymond Waterloo Census-designated place Washburn Other unincorporated communities Blessing Dewar Eagle Center Finchford Glasgow Voorhies Townships Black Hawk County is divided into seventeen townships: Barclay Bennington Big Creek Black Hawk Cedar Cedar Falls Eagle East Waterloo Fox Lester Lincoln Mount Vernon Orange Poyner Spring Creek Union Washington Population ranking The population ranking of the following table is based on the 2020 census of Black Hawk County. † county seat Politics Black Hawk County has been a Democratic stronghold in Iowa since the late 1980s. In presidential politics, it is one of the most Democratic counties in Iowa. As the state swung hard to the right in the 2010s and 2020s, Black Hawk County -- as a major population center, in accordance with most other population centers nationwide -- has remained staunchly Democratic. See also National Register of Historic Places listings in Black Hawk County, Iowa Impact of the 2019–20 coronavirus pandemic on the meat industry in the United States References External links Black Hawk County government's website Waterloo – Cedar Falls metropolitan area 1843 establishments in Iowa Territory Populated places established in 1843