Selby is a city in Walworth County, South Dakota, United States. The population was 642 at the 2010 census. It is the county seat of Walworth County.
Selby is located at 45°30′20″N 100°1′53″W / 45.50556°N 100.03139°W / 45.50556; -100.03139 (45.505692, -100.031369).
According to the United States Census Bureau, the city has a total area of 0.71 square miles (1.84 km), all land.
Selby has been assigned the ZIP code 57472.
As of the census of 2010, there were 642 people, 300 households, and 175 families residing in the city. The population density was 904.2 inhabitants per square mile (349.1/km). There were 334 housing units at an average density of 470.4 per square mile (181.6/km). The racial makeup of the city was 96.7% White, 2.0% Native American, and 1.2% from two or more races. Hispanic or Latino of any race were 0.5% of the population.
There were 300 households of which 19.0% had children under the age of 18 living with them, 51.3% were married couples living together, 4.7% had a female householder with no husband present, 2.3% had a male householder with no wife present, and 41.7% were non-families. 39.0% of all households were made up of individuals and 22.6% had someone living alone who was 65 years of age or older. The average household size was 1.98 and the average family size was 2.62.
The median age in the city was 52.9 years. 16% of residents were under the age of 18; 3.4% were between the ages of 18 and 24; 18.7% were from 25 to 44; 27.8% were from 45 to 64; and 34.1% were 65 years of age or older. The gender makeup of the city was 51.2% male and 48.8% female.
As of the census of 2000, there were 736 people, 308 households, and 199 families residing in the city. The population density was 882.7 people per square mile (342.4/km²). There were 335 housing units at an average density of 401.8 per square mile (155.8/km²). The racial makeup of the city was 98.10% White, 1.36% Native American, 0.14% from other races, and 0.41% from two or more races. Hispanic or Latino of any race were 0.27% of the population.
There were 308 households out of which 23.4% had children under the age of 18 living with them, 57.1% were married couples living together, 5.8% had a female householder with no husband present, and 35.1% were non-families. 34.1% of all households were made up of individuals and 21.4% had someone living alone who was 65 years of age or older. The average household size was 2.16 and the average family size was 2.74.
In the city, the population was spread out with 20.4% under the age of 18, 3.4% from 18 to 24, 20.5% from 25 to 44, 25.3% from 45 to 64, and 30.4% who were 65 years of age or older. The median age was 51 years. For every 100 females, there were 92.7 males. For every 100 females age 18 and over, there were 86.6 males.
The median income for a household in the city was $27,639, and the median income for a family was $37,500. Males had a median income of $26,563 versus $18,214 for females. The per capita income for the city was $16,433. About 4.7% of families and 8.3% of the population were below the poverty line, including 2.6% of those under age 18 and 16.1% of those age 65 or over.
Selby South Dakota neighborhoods include: Alcester, Baltic, Black Hawk, Box Elder, Brandon, Buffalo Ridge, Camp Crook, Canton, Caputa, Central City, Chancellor, Colton, Creighton, Crooks, Custer, Deadwood, Dell Rapids, Elkton, Ellsworth Afb, Garretson, Hartford, Hermosa, Hill City, Howes, Humboldt, Keystone, Lead, Ludlow, Montrose, Nemo, New Underwood, North Sioux City, Owanka, Parker, Quinn, Rapid City, Renner, Rowena, Saint Onge, Scenic, Sherman, Silver City, Sioux Falls, Spearfish, Sturgis, Valley Springs, Wall, Wanblee, Wasta, Whitewood