Thayer
- County:
- Sangamon County
- County Seat:
- No
- Area (mi²):
- 0.61
- State:
- Illinois
Thayer is a village located in Sangamon County, Illinois. Thayer has a 2026 population of 616. Thayer is currently declining at a rate of -0.16% annually and its population has decreased by -2.38% since the most recent census, which recorded a population of 631 in 2020.
The median household income in Thayer is $62,083 with a poverty rate of 10.46%. The median age in Thayer is 46.4 years: 48.3 years for males, and 45.6 years for females. For every 100 females there are 79.4 males.