Roslyn
- County:
- Day County
- County Seat:
- No
- Area (mi²):
- 0.218
- State:
- South Dakota
Roslyn is a town located in Day County, South Dakota. Roslyn has a 2026 population of 180. Roslyn is currently declining at a rate of -2.17% annually and its population has decreased by -1.64% since the most recent census, which recorded a population of 183 in 2020.
The median household income in Roslyn is $49,375 with a poverty rate of 15%. The median age in Roslyn is 53.1 years: 53.3 years for males, and 52.9 years for females. For every 100 females there are 90.9 males.