De Smet
- County:
- Kingsbury County
- County Seat:
- Yes
- Area (mi²):
- 1.158
- State:
- South Dakota
De Smet is a city located in Kingsbury County, South Dakota. De Smet has a 2026 population of 1,037. It is also the county seat of Kingsbury County. De Smet is currently declining at a rate of -0.77% annually and its population has decreased by -2.9% since the most recent census, which recorded a population of 1,068 in 2020.
The median household income in De Smet is $67,321 with a poverty rate of 4.58%. The median age in De Smet is 47.3 years: 47.1 years for males, and 47.4 years for females. For every 100 females there are 92.4 males.