Piatt County
Also known as Piatt County, Illinois, Piatt County, IL
county in Illinois, United States
Key facts
- Country
- United States
- State
- Illinois
- Named after
- James A. Piatt
- Seat
- Monticello
- Largest city
- Monticello
- Total
- 439 sq mi (1,140 km )
- Land
- 439 sq mi (1,140 km )
- Water
- 0.3 sq mi (0.78 km ) 0.06%
- Estimate 2025
- 16,791
- Density
- 38.0/sq mi (14.7/km )
- Time zone
- UTC−6 ( Central )
- Summer dst
- UTC−5 ( CDT )
- Congressional districts
Article
Piatt County is a county in Illinois. According to the 2020 United States census, it had a population of 16,673. Its county seat is Monticello.
Piatt County is part of the Champaign-Urbana Metropolitan Area.