Union County, Illinois Population 2026

Updated April 2026 · US Census ACS 2023 5-Year Estimates · 61st-largest in Illinois

The population of Union County, Illinois is 16,972 as of the 2023 American Community Survey, making it the 61st-largest county in Illinois. The median household income is $56,420, the median home value is $131,700, and the median age is 44.3.

The population of Union County has declined 4.8% since 2010 (17,729 → 16,886), a -0.35% annualized rate.

Union County within Illinois · Source: US Census TIGER/Line via us-atlas

16,972

Population

-0.35%

Annual growth

People / sq mi

$56,420

Median Income

$131,700

Median Home Value

Union County covers 413 sq mi of land at 41.1 people per square mile.

About Union County, IL

Age is the most distinctive thing about Union County: a median age of 44.3, older than the national median. Union County is a county in Illinois with a population of 16,972.

Household earnings are middling, with a median of $56,420 — below the US median of $78,538. Roughly 12.4% of residents fall below the poverty line, close to the national 12.4%. Housing is relatively affordable, with a median home value of $131,700, with typical rent around $658.

Degree attainment is mid-range for US counties: 20.9% of adults hold a four-year degree, below the national 35.0%. Just 5.6% of workers are home-based, below the national 14.0%, and the average commute runs about 26 minutes each way.

The age structure shapes everything downstream in Union County — from housing demand to the mix of working-age earners reflected in the income figures above.

Union County Population History (2010-2024)

The county of Union County had a population of 17,729 in 2010 and 16,886 in 2024, a -4.8% growth over 14 years. The peak was 17,729 in 2010. Average annual growth rate: -0.34%.

Union County population, 2010–2024 · Source: U.S. Census Bureau — decennial census & Population Estimates

16,886

Population (2024)

17,729

Population (2010)

17,729

Peak (2010)

-0.34%

Avg Annual Growth

Year	Population	Change	Annual %	Source
2010	17,729	-	-	estimate
2011	17,690	-39	-0.22%	estimate
2012	17,609	-81	-0.46%	estimate
2013	17,541	-68	-0.39%	estimate
2014	17,404	-137	-0.78%	estimate
2015	17,285	-119	-0.68%	estimate
2016	17,120	-165	-0.95%	estimate
2017	16,982	-138	-0.81%	estimate
2018	16,853	-129	-0.76%	estimate
2019	16,693	-160	-0.95%	estimate
2020	17,298	+605	+3.62%	estimate
2021	17,035	-263	-1.52%	estimate
2022	16,901	-134	-0.79%	estimate
2023	16,866	-35	-0.21%	estimate
2024	16,886	+20	+0.12%	estimate

Race & Ethnicity

White	90.5%
Black or African American	0.8%
Asian	0.0%
Hispanic or Latino (any race)	1.4%
Two or More Races	0.1%

Age & Sex

44.3

Median Age

49.1%

Female

50.9%

Male

22.0%

Age 65+

Age Distribution

Under 5

5.4%

5–9

5.3%

10–14

6.3%

15–19

6.4%

20–24

4.5%

25–34

10.9%

35–44

11.8%

45–54

13.0%

55–59

7.4%

60–64

6.7%

65–74

12.4%

75–84

6.8%

85+

2.8%

Children (under 15): 17.0% · Seniors (65+): 22.0%

Income & Poverty

Median household income	$56,420$-25,282 vs state
Mean household income	$75,913
Per-capita income	$31,962
Poverty rate	12.4%+4.2% vs state
Unemployment rate	2.7%
Employment-to-population	48.4%

Top Industries by Employment

Professional & business services

28.8%

Construction

8.6%

Retail trade

8.3%

Education & health care

8.2%

Public administration

7.8%

Manufacturing

7.4%

Finance & real estate

5.7%

Arts, entertainment & food

5.3%

The largest employment sector in Union County is professional & business services, accounting for 28.8% of workers.

How residents commute

0.0%

Drive alone

1.1%

Carpool

84.1%

Public transit

5.6%

Work from home

25.9 min

Avg commute

Housing

$131,700$-118,800 vs state

Median home value

$658

Median rent

76.8%

Homeownership rate

7,861

Total housing units

88.0%

Occupied

12.0%

Vacant

23.2%

Renter-occupied

Social & access

93.4%

With health insurance

82.0%

With broadband internet

26.8%

Foreign-born

7.1%

Veterans (18+)

19.3%

With a disability

94.7%

Speak language other than English at home

Education

87.0%

High School+

20.9%

Bachelor's+

Largest cities in Illinois

Chicago (2,707,648)Aurora (179,867)Joliet (149,785)Naperville (149,424)Rockford (147,649)Elgin (114,106)Springfield (113,714)Peoria (112,126)Waukegan (88,919)Champaign (88,822)All Illinois cities →

Other counties in Illinois

Cook County (5,185,812)DuPage County (927,263)Lake County (711,885)Will County (698,450)Kane County (516,097)McHenry County (311,366)Winnebago County (283,289)Madison County (264,631)St. Clair County (254,777)Champaign County (206,098)All Illinois counties →

Part of Illinois

Illinois demographic profile All Illinois data →

Metro areas in Illinois

Chicago (9,359,555)St. Louis (2,809,414)Davenport (381,864)Peoria (365,773)Rockford (336,605)Champaign (236,196)Springfield (207,386)Bloomington (170,882)All US metros →

County rankings

US Counties by Population Richest US Counties by Median Household Income Expensive US Counties by Home Value Educated US Counties Counties With Highest Poverty Rates Youngest US Counties by Median Age Oldest US Counties by Median Age Cheapest US Counties by Median Home Value Racially Diverse US Counties Counties With Largest Hispanic Population All rankings →

Frequently Asked Questions

Union County, Illinois has a population of 16,972 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 61st-largest county in Illinois. Population density is 41 people per square mile.

The population of Union County has declined 4.8% since 2010 (17,729 → 16,886), a -0.35% annualized rate.

The median household income in Union County, Illinois is $56,420, with mean (average) household income of $75,913 and per-capita income of $31,962. 12.4% of residents live below the federal poverty level.

In Union County, the largest racial and ethnic groups are White (90.5%), Hispanic or Latino (1.4%), Black or African American (0.8%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.

The median age in Union County, Illinois is 44.3 years. Residents are 49.1% female and 50.9% male.

The median home value in Union County is $131,700 and median monthly rent is $658. 76.8% of occupied housing units are owner-occupied. The county has 7,861 total housing units, 12.0% of which are vacant.

The largest employment sector in Union County, Illinois is professional, scientific, and management services, employing 28.8% of workers. The unemployment rate is 2.7%.

Chicago is among the largest cities associated with Union County, Illinois, with a population of 2,707,648.