Adams County, Illinois Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 23rd-largest in Illinois
The population of Adams County, Illinois is 65,166 as of the 2023 American Community Survey, making it the 23rd-largest county in Illinois. The median household income is $64,962, the median home value is $155,900, and the median age is 41.1.
The population of Adams County has declined 4.5% since 2010 (67,158 → 64,109), a -0.33% annualized rate.
65,166
Population
-0.33%
Annual growth
76
People / sq mi
$64,962
Median Income
$155,900
Median Home Value
Adams County covers 855 sq mi of land at 76.2 people per square mile.
About Adams County, IL
Adams County is defined demographically by education — 27.0% of adults hold a bachelor’s degree, below the national average. With 65,166 residents, Adams County is a county in Illinois. It ranks #23 among counties in Illinois by population.
The typical household here earns about $64,962, below the US median of $78,538. The poverty rate is 8.1%, below the national 12.4%. Homes carry a median value of $155,900, with typical rent around $826.
College attainment is above the local norm at 27.0%, below the national 35.0%. About 6.7% of the workforce is home-based, below the national 14.0%, and the average commute runs about 17 minutes each way.
The education numbers are the throughline: a college-heavy population in Adams County usually coincides with higher incomes and a workforce concentrated in professional and information industries.
Adams County Population History (2010-2024)
The county of Adams County had a population of 67,158 in 2010 and 64,109 in 2024, a -4.5% growth over 14 years. The peak was 67,214 in 2011. Average annual growth rate: -0.33%.
64,109
Population (2024)
67,158
Population (2010)
67,214
Peak (2011)
-0.33%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 67,158 |
| 2011 | 67,214 |
| 2012 | 67,149 |
| 2013 | 67,005 |
| 2014 | 66,983 |
| 2015 | 66,850 |
| 2016 | 66,490 |
| 2017 | 66,073 |
| 2018 | 65,603 |
| 2019 | 65,402 |
| 2020 | 65,622 |
| 2021 | 65,077 |
| 2022 | 64,526 |
| 2023 | 64,435 |
| 2024 | 64,109 |
Race & Ethnicity
| White | 91.0% |
| Black or African American | 3.6% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 0.6% |
| Two or More Races | 0.0% |
Age & Sex
41.1
Median Age
51.0%
Female
49.0%
Male
20.1%
Age 65+
Age Distribution
Children (under 15): 19.1% · Seniors (65+): 20.1%
Income & Poverty
| Median household income | $64,962$-16,740 vs state |
| Mean household income | $83,547 |
| Per-capita income | $36,317 |
| Poverty rate | 8.1%-0.1% vs state |
| Unemployment rate | 2.3% |
| Employment-to-population | 62.9% |
Top Industries by Employment
The largest employment sector in Adams County is professional & business services, accounting for 26.9% of workers.
How residents commute
0.5%
Drive alone
2.5%
Carpool
80.5%
Public transit
6.7%
Work from home
17.0 min
Avg commute
Housing
$155,900$-94,600 vs state
Median home value
$826
Median rent
72.5%
Homeownership rate
30,283
Total housing units
91.7%
Occupied
8.3%
Vacant
27.5%
Renter-occupied
Social & access
95.2%
With health insurance
89.7%
With broadband internet
21.6%
Foreign-born
8.1%
Veterans (18+)
17.6%
With a disability
97.3%
Speak language other than English at home
Education
93.5%
High School+
27.0%
Bachelor's+
Largest cities in Illinois
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County rankings
Frequently Asked Questions
Adams County, Illinois has a population of 65,166 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 23rd-largest county in Illinois. Population density is 76 people per square mile.
The population of Adams County has declined 4.5% since 2010 (67,158 → 64,109), a -0.33% annualized rate.
The median household income in Adams County, Illinois is $64,962, with mean (average) household income of $83,547 and per-capita income of $36,317. 8.1% of residents live below the federal poverty level.
In Adams County, the largest racial and ethnic groups are White (91.0%), Black or African American (3.6%), Hispanic or Latino (0.6%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.
The median age in Adams County, Illinois is 41.1 years. Residents are 51.0% female and 49.0% male.
The median home value in Adams County is $155,900 and median monthly rent is $826. 72.5% of occupied housing units are owner-occupied. The county has 30,283 total housing units, 8.3% of which are vacant.
The largest employment sector in Adams County, Illinois is professional, scientific, and management services, employing 26.9% of workers. The unemployment rate is 2.3%.
Chicago is among the largest cities associated with Adams County, Illinois, with a population of 2,707,648.
Adams County, IL Climate
Adams County, IL has an average annual temperature of 11.2°C (52°F) and receives about 990 mm of precipitation per year. The warmest month is July and the coldest is January. Figures are 1970–2000 climate normals.
11.2°C
Avg Temp
990
Precip (mm/yr)
Jul
Hottest Month
Jan
Coldest Month
| Month | Avg (°C/°F) | Precip |
|---|---|---|
| January | -4° / 24° | 34 mm |
| February | -1° / 30° | 38 mm |
| March | 5° / 41° | 74 mm |
| April | 12° / 53° | 98 mm |
| May | 17° / 63° | 116 mm |
| June | 22° / 72° | 96 mm |
| July | 25° / 76° | 115 mm |
| August | 24° / 74° | 91 mm |
| September | 19° / 66° | 111 mm |
| October | 13° / 55° | 85 mm |
| November | 5° / 42° | 72 mm |
| December | -1° / 30° | 60 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 Adams County, IL
The most comfortable months to visit Adams County, IL are typically June, August and September, when temperatures are mildest and rainfall is relatively low. The hottest month is July (around 31°C high). The coldest is January (near -9°C low). May is usually the wettest month.
Where to stay near Adams County
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Data from the American Community Survey (ACS) 5-Year estimates.
Source: U.S. Census Bureau ACS, 2026.