Warner is a town in Brown County, South Dakota, United States. The population was 457 at the 2010 census.
The town's name is derived from Warren Tarbox, a pioneer settler.
Warner is located at 45°19′31″N 98°29′47″W.
According to the United States Census Bureau, the town has a total area of 0.28 square miles (0.73 km2), all land.
Warner has been assigned the ZIP code 57479 and the FIPS place code 68740.
As of the census of 2010, there were 457 people, 166 households, and 130 families residing in the town. The population density was 1,632.1 inhabitants per square mile (630.2/km2). There were 171 housing units at an average density of 610.7 per square mile (235.8/km2). The racial makeup of the town was 95.8% White, 0.4% African American, 1.5% Native American, 0.7% Asian, and 1.5% from two or more races. Hispanic or Latino of any race were 0.9% of the population.
There were 166 households, of which 46.4% had children under the age of 18 living with them, 67.5% were married couples living together, 6.0% had a female householder with no husband present, 4.8% had a male householder with no wife present, and 21.7% were non-families. 18.1% of all households were made up of individuals, and 5.4% had someone living alone who was 65 years of age or older.