Marvin is a town in Grant County, South Dakota, United States. The population was 19 at the 2020 census.
Marvin was originally called Grade Siding; during the search for what residents considered a more suitable name, the presence of a Marvin brand safe in town caused the new name to be selected.
thumb|Marvin, South Dakota Fire Hall
Geography
Marvin is located in the headwaters region of the Whetstone River.
According to the United States Census Bureau, the town has a total area of , all land.
Demographics
2010 census
As of the census of 2010, there were 34 people, 15 households, and 10 families residing in the town. The population density was . There were 21 housing units at an average density of . The racial makeup of the town was 85.3% White, 5.9% Native American, and 8.8% from two or more races.
There were 15 households, of which 26.7% had children under the age of 18 living with them, 60.0% were married couples living together, 6.7% had a male householder with no wife present, and 33.3% were non-families. 33.3% of all households were made up of individuals, and 13.4% had someone living alone who was 65 years of age or older. The average household size was 2.27 and the average family size was 2.90.
The median age in the town was 47.5 years. 14.7% of residents were under the age of 18; 8.7% were between the ages of 18 and 24; 11.8% were from 25 to 44; 47% were from 45 to 64; and 17.6% were 65 years of age or older. The gender makeup of the town was 52.9% male and 47.1% female.
2000 census
As of the census