Fairfax
- County:
- Gregory County
- County Seat:
- No
- Area (mi²):
- 0.303
- State:
- South Dakota
Fairfax is a town located in Gregory County, South Dakota. Fairfax has a 2026 population of 103. Fairfax is currently growing at a rate of 0.98% annually and its population has increased by 4.04% since the most recent census, which recorded a population of 99 in 2020.
The median household income in Fairfax is $72,656 with a poverty rate of 5.88%. The median age in Fairfax is 48.2 years: 32.5 years for males, and 53.4 years for females. For every 100 females there are 56.6 males.