Piatt County Flag

Piatt County

State:
Illinois
County Seat:
Monticello

Piatt County's 2026 population is estimated at 16,444, reflecting a -0.56% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Piatt County is the 63rd largest county in Illinois. The 2010 population was 16,710 and has grown -1.59% since 2010.

16,444
Total Population
37
Population Density (mi²)
63
Population Rank (State)
-92 -0.56%
Annual Population Growth

Piatt County Population

Demographics

Economics and Income Statistics