Piatt County Flag

Piatt County

State:
Illinois
County Seat:
Monticello

Piatt County's estimated 2026 population is 16,940 with a growth rate of 0.89% in the past year according to the most recent United States census data. Piatt County is the 61st largest county in Illinois. The 2010 population was 16,710 and has seen a growth of 1.38% since that time.

16,940
Total Population
39
Population Density (mi²)
61
Population Rank (State)
149 0.89%
Annual Population Growth

Piatt County Population

Demographics

Economics and Income Statistics