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 -0.79% annually and its population has decreased by -3.08% since the most recent census, which recorded a population of 130 in 2020.
The median age in Groton is 58.6 years: 0 years for males, and 0 years for females. For every 100 females there are 53.8 males.