Lake Mills is a city in Jefferson County, Wisconsin, United States. The population was 5,708 at the 2010 census. The city is located partially within the Town of Lake Mills.GeographyLake Mills is located at .According to the United States Census Bureau, the city has a total area of 4.44sqmi, of which 4.06sqmi is land and 0.38sqmi is water.Demographics2010 censusAs of the census of 2010, there were 5,708 people, 2,319 households, and 1,503 families residing in the city. The population density was 1405.9PD/sqmi. There were 2,776 housing units at an average density of 683.7/sqmi. The racial makeup of the city was 96.1% White, 0.7% African American, 0.2% Native American, 0.5% Asian, 1.2% from other races, and 1.3% from two or more races. Hispanic or Latino of any race were 3.8% of the population.There were 2,319 households of which 32.4% had children under the age of 18 living with them, 52.4% were married couples living together, 8.7% had a female householder with no husband present, 3.7% had a male householder with no wife present, and 35.2% were non-families. 28.2% of all households were made up of individuals and 11.6% had someone living alone who was 65 years of age or older. The average household size was 2.42 and the average family size was 3.00.