In 2022, the population of Chelsea was 17, a 0.00% decrease year-by-year from 2021. Previously, in 2021, Chelsea's population was 17, a decline of 0.00% compared to a population of 17 in 2020.
The median age in Chelsea, SD is 36.2, as per 2021 ACS 5-Year Estimates. Of the total population, 2.99% were under the age of 15, 46.27% aged 15 to 29, 29.85% aged 30 to 64, 20.90% aged 65 to 84, and 0.00% were 85 years of age and older.