Frankfort is a city in Spink County, South Dakota, United States. The population was 149 at the 2010 census.
Frankfort was platted in 1882. Some say it was named after Frankfurt, in Germany, while others believe the town has the name of Frankfort I. Fisher, a pioneer settler. A post office has been in operation in Frankfort since 1882.
Frankfort is located at 44°52′39″N 98°18′22″W (44.877368, -98.306068).
According to the United States Census Bureau, the city has a total area of 0.79 square miles (2.05 km2), all land.
Frankfort has been assigned the ZIP code 57440 and the FIPS place code 22580.
As of the census of 2010, there were 149 people, 61 households, and 37 families residing in the city. The population density was 188.6 inhabitants per square mile (72.8/km2). There were 82 housing units at an average density of 103.8 per square mile (40.1/km2). The racial makeup of the city was 94.6% White, 3.4% Native American, and 2.0% from other races. Hispanic or Latino of any race were 2.0% of the population.