Mercer County, Illinois Demographics 2026

Name: Mercer County, Illinois Demographics
Creator: U.S. Census Bureau
License: https://www.census.gov/data/developers/about/terms-of-service.html

Mercer County, Illinois has a population of 15,495, the 69th most populous county in Illinois. The median household income is $74,182 and the median home value is $146,700. The poverty rate is 8.9%.

Data vintage: U.S. Census Bureau ACS 2020–2024 5-Year Estimates · refreshed July 2026 · Methodology & source notes

Mercer County Quick Facts

Population 15,495

Median Household Income $74,182

Median Home Value $146,700

Poverty Rate 8.9%

Unemployment Rate 3.1%

Median Age 44.7 years

Homeownership Rate 83.8%

Affordability Ratio 2.0x

Bachelor's Degree+ 20.9%

High School Graduation 93.9%

Cities/Places 14

Population 15,495 69th of 102

Median Income $74,182 11% lower than state

Poverty Rate 8.9%

Unemployment 3.1%

How Mercer County Changed

Change from the 2019–2023 ACS period to 2020–2024. These are rolling five-year estimates, not year-over-year measurements.

Metric	2019–2023	2020–2024	Change
Population	15,619	15,495	-0.8%
Median household income	$71,710	$74,182	+3.4%
Median home value	$139,300	$146,700	+5.3%

Median Household Income

Mercer

$74,182

$83,390

National

$80,734

Median Home Value

Mercer

$146,700

$263,300

National

$332,700

Economy & Housing

Household Income Distribution

Under $25K 14.1%

$25K-$50K 19.1%

$50K-$100K 28.8%

$100K+ 37.9%

Detailed income brackets

Under $10K

4.9%

$10K-$15K

2.5%

$15K-$20K

3.2%

$20K-$25K

3.5%

$25K-$30K

4.5%

$30K-$35K

2.4%

$35K-$40K

3.5%

$40K-$45K

3.2%

$45K-$50K

5.5%

$50K-$60K

7.0%

$60K-$75K

10.4%

$75K-$100K

11.4%

$100K-$125K

12.7%

$125K-$150K

7.7%

$150K-$200K

10.2%

$200K+

7.3%

Employment

3.1% Unemployment Rate State: 5.8%|National: 5.2%

60.8% Labor Force Participation

Housing Overview

Owner 83.8%

Renter 16.2%

Affordability Index Very Affordable

2.0x home value to income ratio

Median gross rent $786/mo 12.7% of median household income annually

People & Demographics

Age Distribution

Under 18

20.8%

18-34

17.7%

35-54

24.8%

55-74

27.4%

75+

9.3%

Race & Ethnicity

Diversity Index

Very Low Diversity

A less diverse community where one racial or ethnic group represents a large majority.

State average: 61 | National average: 61

Education

Educational Attainment (Adults 25+)

Cities & Places in Mercer County

City	Population	Median Income	Poverty	Home Value
Aledo	3,668	$72,292	12.6%	$147,600
Viola	899	$72,500	9.3%	$120,000
Windsor	704	$59,333	13.7%	$109,800
Sherrard	691	$98,750	9.3%	$150,200
Matherville	657	$86,500	7.6%	$134,800
New Boston	648	$60,662	16.4%	$95,400
Keithsburg	490	$44,625	17.1%	$65,900
Joy	387	$56,250	12.3%	$76,100
Seaton	228	$60,625	9.2%	$109,200
North Henderson	191	$74,231	0.0%	$66,700
Preemption	127	$86,406	0.0%	$110,900
Cable	122	$104,375	0.0%	$329,000
Swedona	64	N/A	0.0%	N/A
Millersburg	33	N/A	45.5%	N/A

Explore Illinois Rankings

Cities by Population All cities ranked by size Richest Cities Ranked by median income Most Educated By bachelor's degree rate Most Affordable By housing affordability

Population Overview

Mercer County is located in Illinois with a total population of 15,495. It is the 69th most populous county out of 102 in Illinois. The county encompasses 14 Census-designated places.

Age Demographics

The median age in Mercer County is 44.7 years. This is 15% higher than the state median of 39.0 years.

Economy, Income & Housing

The median household income in Mercer County is $74,182. This is 11% lower than the state median of $83,390. It is also 8% lower than the national median of $80,734. The poverty rate stands at 8.9%. This is 24% lower than the state poverty rate of 11.8%. The unemployment rate is 3.1%. This is 46% lower than the state rate of 5.8%. The median home value is $146,700. Housing costs are 44% lower than the state median of $263,300. With a home-value-to-income ratio of just 2.0x, Mercer County is one of the most affordable housing markets in the area. 83.8% of occupied housing units are owner-occupied. This homeownership rate is 25% higher than the state average of 67.1%.

Race & Ethnicity

Mercer County has a predominantly White (non-Hispanic) population, comprising 93.1% of all residents. Hispanic or Latino residents account for 3.5%. The White (non-Hispanic) population is significantly higher than the state average (93.1% vs 58.1%). The Black or African American population (0.6%) is well below the state average of 13.3%. The Hispanic or Latino population (3.5%) is well below the state average of 18.8%. The Asian population (0.4%) is well below the state average of 5.9%.

Education

20.9% of residents aged 25 and older hold a bachelor's degree or higher. This is 45% lower than the state rate of 37.9%. Nationally, 35.7% of adults hold at least a bachelor's degree. The high school graduation rate (or equivalent) is 93.9%.

Data Sources & Methodology

All figures for Mercer County come from the U.S. Census Bureau's American Community Survey (ACS) 2020–2024 5-Year Estimates, with comparisons drawn against Illinois and national averages from the same dataset. See our methodology page for how each metric is defined, or data.census.gov for official tables with margins of error.

Frequently Asked Questions

What is the population of Mercer County, Illinois?

Mercer County has a population of 15,495, making it the 69th most populous county in Illinois.

What is the median income in Mercer County?

The median household income in Mercer County is $74,182 with a poverty rate of 8.9%.

How many cities are in Mercer County, Illinois?

Mercer County contains 14 Census-designated places.