Groton
- County:
- Brown County
- County Seat:
- No
- Area (mi²):
- 46.255
- State:
- South Dakota
Groton is located in Brown County, South Dakota. Groton has a 2025 population of 126. Groton is currently declining at a rate of -1.56% annually and its population has decreased by -3.82% since the most recent census, which recorded a population of 131 in 2020.
The median age in Groton is 58.6 years: 0 years for males, and 0 years for females.