Clay City
- County:
- Clay County
- County Seat:
- No
- Area (mi²):
- 1.782
- State:
- Illinois
Clay City is a village located in Clay County, Illinois. Clay City has a 2026 population of 819. Clay City is currently declining at a rate of -0.97% annually and its population has decreased by -3.99% since the most recent census, which recorded a population of 853 in 2020.