Piatt County, Illinois Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 62nd-largest in Illinois
The population of Piatt County, Illinois is 16,702 as of the 2023 American Community Survey, making it the 62nd-largest county in Illinois. The median household income is $87,516, the median home value is $173,200, and the median age is 42.5.
The population of Piatt County has declined 0.5% since 2010 (16,710 → 16,628), a -0.04% annualized rate.
16,702
Population
-0.04%
Annual growth
38
People / sq mi
$87,516
Median Income
$173,200
Median Home Value
Piatt County covers 439 sq mi of land at 38.0 people per square mile.
About Piatt County, IL
Homeownership is the standout figure in Piatt County: 85.4% of homes are owner-occupied, higher than the national rate. Piatt County is a county in Illinois with a population of 16,702.
Earnings sit at the high end: a median household income of $87,516, above the US median of $78,538. Poverty is among the lowest of comparable US counties, at 4.6% — below the national 12.4%. Median home value is $173,200, with typical rent around $950.
About 31.9% of adults 25 and older have a bachelor’s degree, below the 35.0% national figure. Around 6.9% of workers work from home, below the national 14.0%, and the average commute runs about 24 minutes each way.
The ownership rate anchors the housing story in Piatt County, and tends to move with the age structure and home-value figures above.
Piatt County Population History (2010-2024)
The county of Piatt County had a population of 16,710 in 2010 and 16,628 in 2024, a -0.5% growth over 14 years. The peak was 16,764 in 2021. Average annual growth rate: -0.03%.
16,628
Population (2024)
16,710
Population (2010)
16,764
Peak (2021)
-0.03%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 16,710 |
| 2011 | 16,683 |
| 2012 | 16,505 |
| 2013 | 16,437 |
| 2014 | 16,414 |
| 2015 | 16,356 |
| 2016 | 16,511 |
| 2017 | 16,427 |
| 2018 | 16,375 |
| 2019 | 16,391 |
| 2020 | 16,683 |
| 2021 | 16,764 |
| 2022 | 16,678 |
| 2023 | 16,720 |
| 2024 | 16,628 |
Race & Ethnicity
| White | 95.6% |
| Black or African American | 1.6% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 0.7% |
| Two or More Races | 0.0% |
Age & Sex
42.5
Median Age
50.4%
Female
49.6%
Male
20.5%
Age 65+
Age Distribution
Children (under 15): 18.0% · Seniors (65+): 20.5%
Income & Poverty
| Median household income | $87,516+$5,814 vs state |
| Mean household income | $106,362 |
| Per-capita income | $43,547 |
| Poverty rate | 4.6%-3.6% vs state |
| Unemployment rate | 2.2% |
| Employment-to-population | 62.5% |
Top Industries by Employment
The largest employment sector in Piatt County is professional & business services, accounting for 30.7% of workers.
How residents commute
0.3%
Drive alone
1.5%
Carpool
85.1%
Public transit
6.9%
Work from home
23.7 min
Avg commute
Housing
$173,200$-77,300 vs state
Median home value
$950
Median rent
85.4%
Homeownership rate
7,380
Total housing units
92.8%
Occupied
7.2%
Vacant
14.6%
Renter-occupied
Social & access
97.0%
With health insurance
94.6%
With broadband internet
15.2%
Foreign-born
6.1%
Veterans (18+)
12.1%
With a disability
97.8%
Speak language other than English at home
Education
96.0%
High School+
31.9%
Bachelor's+
Largest cities in Illinois
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County rankings
Frequently Asked Questions
Piatt County, Illinois has a population of 16,702 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 62nd-largest county in Illinois. Population density is 38 people per square mile.
The population of Piatt County has declined 0.5% since 2010 (16,710 → 16,628), a -0.04% annualized rate.
The median household income in Piatt County, Illinois is $87,516, with mean (average) household income of $106,362 and per-capita income of $43,547. 4.6% of residents live below the federal poverty level.
In Piatt County, the largest racial and ethnic groups are White (95.6%), Black or African American (1.6%), Hispanic or Latino (0.7%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.
The median age in Piatt County, Illinois is 42.5 years. Residents are 50.4% female and 49.6% male.
The median home value in Piatt County is $173,200 and median monthly rent is $950. 85.4% of occupied housing units are owner-occupied. The county has 7,380 total housing units, 7.2% of which are vacant.
The largest employment sector in Piatt County, Illinois is professional, scientific, and management services, employing 30.7% of workers. The unemployment rate is 2.2%.
Chicago is among the largest cities associated with Piatt County, Illinois, with a population of 2,707,648.
Piatt County, IL Climate
Piatt County, IL has an average annual temperature of 11°C (52°F) and receives about 994 mm of precipitation per year. The warmest month is July and the coldest is January. Figures are 1970–2000 climate normals.
11°C
Avg Temp
994
Precip (mm/yr)
Jul
Hottest Month
Jan
Coldest Month
| Month | Avg (°C/°F) | Precip |
|---|---|---|
| January | -4° / 24° | 46 mm |
| February | -2° / 29° | 46 mm |
| March | 5° / 40° | 83 mm |
| April | 11° / 52° | 102 mm |
| May | 17° / 63° | 104 mm |
| June | 22° / 72° | 96 mm |
| July | 24° / 75° | 113 mm |
| August | 23° / 73° | 99 mm |
| September | 19° / 67° | 83 mm |
| October | 13° / 55° | 68 mm |
| November | 5° / 42° | 79 mm |
| December | -1° / 30° | 75 mm |
1970–2000 normals from WorldClim 2.1 (~9 km grid). Precipitation can be less precise near mountains or coastlines, where rainfall varies sharply over short distances.
Best time to visit Piatt County, IL
The most comfortable months to visit Piatt County, IL are typically June, September and August, when temperatures are mildest and rainfall is relatively low. The hottest month is July (around 30°C high). The coldest is January (near -9°C low). July is usually the wettest month.
Where to stay near Piatt County
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Data from the American Community Survey (ACS) 5-Year estimates.
Source: U.S. Census Bureau ACS, 2026.