As of the census of 2010, there were 2,028 people, 869 households, and 555 families living in the city. The population density was. There were 944 housing units at an average density of. The racial makeup of the city was 98.5% White, 0.8% Asian, 0.1% from other races, and 0.6% from two or more races. Hispanic or Latino of any race were 0.7% of the population. There were 869 households of which 27.0% had children under the age of 18 living with them, 53.4% were married couplesliving together, 7.6% had a female householder with no husband present, 2.9% had a male householder with no wife present, and 36.1% were non-families. 33.0% of all households were made up of individuals and 18.3% 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 2.83. The median age in the city was 45.3 years. 22% of residents were under the age of 18; 5.9% were between the ages of 18 and 24; 21.7% were from 25 to 44; 25% were from 45 to 64; and 25.4% were 65 years of age or older. The gender makeup of the city was 45.8% male and 54.2% female.
2000 census
As of the census of 2000, there were 2,106 people, 888 households, and 575 families living in the city. The population density was 833.8 people per square mile. There were 930 housing units at an average density of 368.2 per square mile. The racial makeup of the city was 98.96% White, 0.19% African American, 0.43% Asian, 0.05% Pacific Islander, 0.09% from other races, and 0.28% from two or more races. Hispanic or Latino of any race were 0.66% of the population. There were 888 households out of which 27.1% had children under the age of 18 living with them, 55.9% were married couples living together, 6.3% had a female householder with no husband present, and 35.2% were non-families. 32.1% of all households were made up of individuals and 20.6% 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 2.88. In the city, the population was spread out with 22.9% under the age of 18, 6.1% from 18 to 24, 22.9% from 25 to 44, 23.2% from 45 to 64, and 24.9% who were 65 years of age or older. The median age was 44 years. For every 100 females, there were 88.5 males. For every 100 females age 18 and over, there were 80.4 males. The median income for a household in the city was $33,417, and the median income for a family was $44,318. Males had a median income of $29,224 versus $20,901 for females. The per capita income for the city was $18,029. About 2.2% of families and 4.2% of the population were below the poverty line, including 5.3% of those under age 18 and 5.4% of those age 65 or over.
Historic sites
There are many historic buildings in Sumner, including the old bank/clock tower, and the old school building, which was built in 1901 and is currently a museum. Sumner has recently built a new library, recreation center, and a park for residents.
