Grundy County, Illinois Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 26th-largest in Illinois
The population of Grundy County, Illinois is 52,920 as of the 2023 American Community Survey, making it the 26th-largest county in Illinois. The median household income is $93,060, the median home value is $259,200, and the median age is 38.6.
The population of Grundy County has grown 7.3% since 2010 (50,155 → 53,835), a +0.51% annualized rate.
52,920
Population
+0.51%
Annual growth
127
People / sq mi
$93,060
Median Income
$259,200
Median Home Value
Grundy County covers 418 sq mi of land at 126.6 people per square mile.
About Grundy County, IL
What sets Grundy County apart is money: median household income runs $93,060, above the US median of $78,538. Grundy County is a county in Illinois with a population of 52,920. It ranks #26 among counties in Illinois by population.
Households here are among the highest-earning of all US counties: median income is $93,060, above the US median of $78,538. Poverty is relatively low for US counties at 4.7%, below the national 12.4%. The median home value is $259,200, with typical rent around $1,137.
24.2% of adults 25 and older hold a bachelor’s degree, below the national average of 35.0%. Remote work is below the national 14.0% at 9.7%, and the average commute runs about 28 minutes each way.
Taken together, the income and housing figures place Grundy County firmly in the higher-cost, higher-earning tier of US counties — a profile that tends to track dense job markets and competitive housing.
Grundy County Population History (2010-2024)
The county of Grundy County had a population of 50,155 in 2010 and 53,835 in 2024, a 7.3% growth over 14 years. The peak was 53,835 in 2024. Average annual growth rate: 0.51%.
53,835
Population (2024)
50,155
Population (2010)
53,835
Peak (2024)
0.51%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 50,155 |
| 2011 | 50,103 |
| 2012 | 50,161 |
| 2013 | 50,183 |
| 2014 | 50,281 |
| 2015 | 50,358 |
| 2016 | 50,325 |
| 2017 | 50,627 |
| 2018 | 51,012 |
| 2019 | 51,031 |
| 2020 | 52,535 |
| 2021 | 52,984 |
| 2022 | 53,153 |
| 2023 | 53,587 |
| 2024 | 53,835 |
Race & Ethnicity
| White | 88.4% |
| Black or African American | 2.1% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 0.7% |
| Two or More Races | 0.0% |
Age & Sex
38.6
Median Age
49.7%
Female
50.3%
Male
14.6%
Age 65+
Age Distribution
Children (under 15): 20.1% · Seniors (65+): 14.6%
Income & Poverty
| Median household income | $93,060+$11,358 vs state |
| Mean household income | $111,929 |
| Per-capita income | $43,744 |
| Poverty rate | 4.7%-3.5% vs state |
| Unemployment rate | 3.1% |
| Employment-to-population | 65.1% |
Top Industries by Employment
The largest employment sector in Grundy County is professional & business services, accounting for 21.0% of workers.
How residents commute
0.6%
Drive alone
0.8%
Carpool
83.8%
Public transit
9.7%
Work from home
27.6 min
Avg commute
Housing
$259,200+$8,700 vs state
Median home value
$1,137
Median rent
75.8%
Homeownership rate
21,324
Total housing units
96.2%
Occupied
3.8%
Vacant
24.2%
Renter-occupied
Social & access
96.3%
With health insurance
95.1%
With broadband internet
12.2%
Foreign-born
7.9%
Veterans (18+)
9.7%
With a disability
92.3%
Speak language other than English at home
Education
94.2%
High School+
24.2%
Bachelor's+
Largest cities in Illinois
Other counties in Illinois
Part of Illinois
Metro areas in Illinois
County rankings
Frequently Asked Questions
Grundy County, Illinois has a population of 52,920 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 26th-largest county in Illinois. Population density is 127 people per square mile.
The population of Grundy County has grown 7.3% since 2010 (50,155 → 53,835), a +0.51% annualized rate.
The median household income in Grundy County, Illinois is $93,060, with mean (average) household income of $111,929 and per-capita income of $43,744. 4.7% of residents live below the federal poverty level.
In Grundy County, the largest racial and ethnic groups are White (88.4%), Black or African American (2.1%), 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 Grundy County, Illinois is 38.6 years. Residents are 49.7% female and 50.3% male.
The median home value in Grundy County is $259,200 and median monthly rent is $1,137. 75.8% of occupied housing units are owner-occupied. The county has 21,324 total housing units, 3.8% of which are vacant.
The largest employment sector in Grundy County, Illinois is professional, scientific, and management services, employing 21.0% of workers. The unemployment rate is 3.1%.
Chicago is among the largest cities associated with Grundy County, Illinois, with a population of 2,707,648.
Grundy County, IL Climate
Grundy County, IL has an average annual temperature of 10°C (50°F) and receives about 916 mm of precipitation per year. The warmest month is July and the coldest is January. Figures are 1970–2000 climate normals.
10°C
Avg Temp
916
Precip (mm/yr)
Jul
Hottest Month
Jan
Coldest Month
| Month | Avg (°C/°F) | Precip |
|---|---|---|
| January | -6° / 22° | 38 mm |
| February | -3° / 27° | 35 mm |
| March | 3° / 38° | 71 mm |
| April | 10° / 50° | 95 mm |
| May | 16° / 61° | 99 mm |
| June | 21° / 70° | 99 mm |
| July | 23° / 74° | 97 mm |
| August | 22° / 72° | 89 mm |
| September | 18° / 65° | 92 mm |
| October | 12° / 53° | 66 mm |
| November | 5° / 40° | 74 mm |
| December | -2° / 28° | 61 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 Grundy County, IL
The most comfortable months to visit Grundy County, IL are typically June, August and July, when temperatures are mildest and rainfall is relatively low. The hottest month is July (around 29°C high). The coldest is January (near -10°C low). May is usually the wettest month.
Where to stay near Grundy County
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Data from the American Community Survey (ACS) 5-Year estimates.
Source: U.S. Census Bureau ACS, 2026.