Thornton is a city in Cerro Gordo County, Iowa, United States. The population was 400 at the time of the 2020 census. It is part of the Mason City Micropolitan Statistical Area. Geography Thornton, Iowa is located at (42.944972, -93.384115). According to the United States Census Bureau, the city has a total area of , all land. Demographics 2010 census As of the census of 2010, there were 422 people, 188 households, and 125 families residing in the city. The population density was . There were 204 housing units at an average density of . The racial makeup of the city was 98.6% White, 0.5% African American, and 0.9% from two or more races. Hispanic or Latino of any race were 0.7% of the population. There were 188 households, of which 27.7% had children under the age of 18 living with them, 56.4% were married couples living together, 6.9% had a female householder with no husband present, 3.2% had a male householder with no wife present, and 33.5% were non-families. 28.7% of all households were made up of individuals, and 13.3% had someone living alone who was 65 years of age or older. The average household size was 2.24 and the average family size was 2.72. The median age in the city was 45.3 years. 20.4% of residents were under the age of 18; 9.2% were between the ages of 18 and 24; 20% were from 25 to 44; 30.1% were from 45 to 64; and 20.4% were 65 years of age or older. The gender makeup of the city was 50.5% male and 49.5% female. Matt Ingebretson is the mayor of Thornton. 2000 census As of the census of 2000, there were 422 people, 183 households, and 124 families residing in the city. The population density was . There were 193 housing units at an average density of . The racial makeup of the city was 98.58% White, 0.24% Native American, 0.71% from other races, and 0.47% from two or more races. Hispanic or Latino of any race were 1.18% of the population. There were 183 households, out of which 24.0% had children under the age of 18 living with them, 59.6% were married couples living together, 5.5% had a female householder with no husband present, and 31.7% were non-families. 29.5% of all households were made up of individuals, and 16.9% had someone living alone who was 65 years