Delmont is a city in southeastern Douglas County, South Dakota, United States. The population was 234 at the 2010 census.
Delmont was laid out in 1886.
Delmont is located at 43°16′1″N 98°9′47″W (43.267013, -98.162996).
According to the United States Census Bureau, the city has a total area of 0.76 square miles (1.97 km2), all land.
Delmont has been assigned the ZIP code 57330 and the FIPS place code 16060.
At the 2010 census, there were 234 people, 110 households and 61 families residing in the city. The population density was 307.9 per square mile (118.9/km2). There were 141 housing units at an average density of 185.5 per square mile (71.6/km2). The racial make-up was 83.3% White, 3.0% African American, 9.0% Native American, 1.7% from other races, and 3.0% from two or more races. Hispanic or Latino of any race were 3.4% of the population.
There were 110 households, of which 22.7% had children under the age of 18 living with them, 46.4% were married couples living together, 5.5% had a female householder with no husband present, 3.6% had a male householder with no wife present, and 44.5% were non-families. 37.3% of all households were made up of individuals, and 19.1% had someone living alone who was 65 years of age or older.