Madison
- County:
- Lake County
- County Seat:
- No
- Area (mi²):
- 4.616
- State:
- South Dakota
Madison is a city located in Lake County, South Dakota. Madison has a 2026 population of 6,086. Madison is currently declining at a rate of -0.18% annually and its population has decreased by -1.22% since the most recent census, which recorded a population of 6,161 in 2020.