As of the census of 2010, there were 1,296 people, 568 households, and 322 families living in the city. The population density was. There were 646 housing units at an average density of. The racial makeup of the city was 97.6% White, 0.6% African American, 0.4% Native American, 0.5% Asian, and 0.8% from two or more races. Hispanic or Latino of any race were 0.9% of the population. There were 568 households of which 30.5% had children under the age of 18 living with them, 37.9% were married couplesliving together, 13.7% had a female householder with no husband present, 5.1% had a male householder with no wife present, and 43.3% were non-families. 38.9% of all households were made up of individuals and 19.7% had someone living alone who was 65 years of age or older. The average household size was 2.28 and the average family size was 3.07. The median age in the city was 38.1 years. 27.2% of residents were under the age of 18; 9% were between the ages of 18 and 24; 22.3% were from 25 to 44; 24.4% were from 45 to 64; and 17% were 65 years of age or older. The gender makeup of the city was 47.4% male and 52.6% female.
2000 census
As of the census of 2000, there were 1,349 people, 564 households, and 354 families living in the city. The population density was 859.0 people per square mile. There were 632 housing units at an average density of 402.4 per square mile. The racial makeup of the city was 97.33% White, 0.15% African American, 0.82% Native American, 0.30% Asian, and 1.41% from two or more races. Hispanic or Latino of any race were 0.59% of the population. There were 564 households out of which 34.9% had children under the age of 18 living with them, 47.0% were married couples living together in Mansfield, Mo 12.1% had a female householder with no husband present 37.1% were classified as "non-families". 34.9% of all households were made up of individuals and 21.1% had someone living alone who was 65 years of age or older. The average household size was 2.39 and the average family size was 3.07. In the city the population was spread out with 29.7% under the age of 18, 9.4% from 18 to 24, 25.7% from 25 to 44, 17.9% from 45 to 64, and 17.3% who were 65 years of age or older. The median age was 34 years. For every 100 females there were 83.0 males. For every 100 females age 18 and over, there were 76.4 males. The median income for a household in the city was $21,875, and the median income for a family was $27,734. Males had a median income of $27,143 versus $15,216 for females. The per capita income for the city was $11,303. About 20.9% of families and 24.2% of the population were below the poverty line, including 29.8% of those under age 18 and 33.6% of those age 65 or over.
In 1894, Laura Ingalls Wilder, along with her husband, Almanzo, and their daughter Rose moved from South Dakota to Mansfield. They remained in the area for the next 60 years and established Rocky Ridge Farm, a large, successful poultry, dairy, and fruit farm on the outskirts of town. Today, their unique 10-room farmhouse is a National Historic Landmark, and the home of the Laura Ingalls Wilder Home and Museum, which attracts thousands of visitors to Mansfield each year. The Wilders also lived for a time in the Rock House purchased for them by their daughter Rose.
