Montgomery County, Illinois

County in IL, US

By Neilsberg Research

Last updated May 1, 2026

Key Indicators

A quick look at key numbers

Population

27,942

Source: U.S. Census Bureau American Community Survey (ACS) 2020-2024 5-Year Estimates

Median Age

42.8

years ∙ half population younger than 42.8, half older

Diversity Index

15.7%

chance two random people differ in race and ethnicity

Nativity

0.8%

foreign-born population

99.2%Native

0.8% Foreign-born

Geographic Context

Location, size, and surroundings

About

Montgomery County is a county in Illinois, United States.

Location

County in IL, US

Co-ordinates

DEC39.228068° N, 89.478141° W

DMS39° 13′ 41.04″ N, 89° 28′ 41.31″ W

Population Density & area

39.7/sq mi (15.33/km²)

Total Area

709.8 sq mi (1,838.2 km²)

Land Area

703.8 sq mi (1,822.7 km²) · 99.16%

Water Area

6 sq mi (15.5 km²) · 0.84%

Demographics & Living

Who lives here, how households are formed, and community composition

Population Composition

Key characteristics of the population

Sex Distribution

53.1% male

Male 53.1%

Female 46.9%

males per 100 females

Montgomery County 113.1

Illinois 97.7

United States 98

Nativity

0.8%

foreign-born population

99.2%Native

0.8% Foreign-born

% Foreign-born

Montgomery County 0.8%

Illinois 14.7%

United States 14.1%

Age Distribution

How the population is spread across age groups

Median Age

42.8

years ∙ half population younger than 42.8, half older

Montgomery County

42.8

Illinois

United States

38.9

Dependency ratio

71.3

dependents per 100 working-age adults

Montgomery County 71.3

Illinois 63.5

United States 64.4

AGE DISTRIBUTION

Distribution of age group

Median age

	Montgomery County	Illinois	United States
Age Group
Children (Under 18)	20.1%	21.8%	22%
Working age (18-64)	58.4%	61.2%	60.8%
Senior (65+)	21.5%	17%	17.2%
Dependency ratio
Total dependency ratio	71.3	63.5	64.4
Child dependency ratio	34.5	35.7	36.1
Old-age dependency ratio	36.8	27.8	28.3

Racial & Ethnic Composition

Racial and ethnic makeup and how it compares

Race & Ethnicity

White

91.7%

Black

3.3%

Asian

0.4%

Hispanic

2.2%

Other

2.4%

Note: White, Black, and Asian refer to individuals belonging to a single race and not of Hispanic origin. Hispanics may be of any race.

Diversity Index

15.7%

chance two random people differ in race and ethnicity

Montgomery County 15.7%

Illinois 60.5%

United States 61.4%

Note: The Diversity Index (DI), based on the Blau Index, measures the probability that two randomly selected individuals differ in race and ethnicity. Values range from 0 (no diversity) to 1 (high diversity) and are shown as percentages.

RACIAL & ETHNIC COMPOSITION

Race & Ethnicity

Percentage of Montgomery County population

	Montgomery County	Illinois	United States
Hispanic or Latino	2.2%	18.8%	19.3%
Mexican	1.4%	14.4%	11.3%
Puerto Rican	0.2%	1.6%	1.8%
Cuban	0%	0.3%	0.8%
Other Hispanic / Latino	0.5%	2.5%	5.5%
Not Hispanic or Latino	97.8%	81.2%	80.7%
One race	95.7%	77.8%	76.4%
White	91.7%	58.1%	57.4%
Black or African American	3.3%	13.3%	11.9%
American Indian and Alaska Native	0.1%	0.1%	0.5%
Asian	0.4%	5.9%	5.9%
Native Hawaiian and Other Pacific Islander	0%	0%	0.2%
Some Other Race	0.2%	0.4%	0.6%
Two or more races (Multiracial)	2.1%	3.4%	4.3%

Household & Families Composition

Household size, type, and family structure

Household structure

58.3% family

Family 58.3%

Non family 41.7%

% family households

Montgomery County 58.3%

Illinois 62.2%

United States 64.2%

Average household size

2.27

persons per household

Montgomery County

2.27

Illinois

2.46

United States

2.53

Household & Family COMPOSITION

Households

Percentage of Montgomery County population

	Montgomery County	Illinois	United States
Total households	11,319	5,036,449	129,227,496
Average houshold size	2.27	2.46	2.53
Family households	6,604	3,130,978	82,990,528
Average family size	2.97	3.14	3.14
Married couple family	5,455	2,282,435	60,637,388
Other families	1,149	848,543	22,353,140
Male householder	360	248,521	6,572,819
Female householder	789	600,022	15,780,321
Non-family households	4,715	1,905,471	46,236,968
One-person households	4,012	1,569,881	37,140,836
Male householder	2,066	712,191	16,871,444
Senior (65+) living alone	675	210,051	5,225,110
Female householder	1,946	857,690	20,269,392
Senior (65+) living alone	1,313	417,870	10,089,070
Other living arrangements	703	335,590	9,096,132

Housing Profile

Housing stock, ownership, rentals, and cost burdens

Total housing units

12,495

housing units

Montgomery County 12,495

Illinois 5,457,452

United States 143,775,355

Occupancy status

90.6% occupied

Occupied 90.6%

Vacant 9.4%

vacancy rate

Montgomery County 9.4%

Illinois 7.7%

United States 10.1%

Housing Characteristics

How the housing supply is structured and used

Types of Housing unit

84.7%

Single family houses

84.7%

Apartments in multi-unit structures

9.3%

Mobile homes

6.1%

Boat, RV, van, etc

Median Year Built

1963

Half of houses were built before 1963, and half after.

Historic ∙ 1939 or earlier

26.5%

Postwar & mid-century ∙ 1940 - 1969

30.5%

Late 20th century ∙ 1970 - 1999

31.3%

Modern ∙ 2000 or later

11.7%

Note: Median year built reflects occupied units only; distribution includes all units.

Housing Characteristics

Units, rooms & bedrooms

Physical characteristics of housing units

	Montgomery County	Illinois	United States
Rooms per unit
Median rooms	5.8	5.6	5.5
1–3 rooms	10.8%	14.6%	15.1%
4–6 rooms	57.8%	50.9%	51.6%
7+ rooms	31.4%	34.6%	33.4%
Bedrooms
No bedroom / studio	4.5%	3.1%	2.9%
1 bedroom	7.7%	11.5%	10.9%
2 bedrooms	32.5%	27.7%	25%
3 bedrooms	39.2%	35.8%	38.7%
4+ bedrooms	16%	21.7%	22.4%
At a glance
Median year built	1963	1971	1981
Total housing units	12,495	5,457,452	143,775,355

Occupancy Profile

Who is inside and how they use it

Homeownership

77.4% owners

Renter-occupied 22.6%

Owner-occupied 77.4%

homeownership rate

Montgomery County 77.4%

Illinois 67.1%

United States 65.2%

Average household size

2.36

Owner-occupied

1.94

Renter-occupied

owner-occupied average size

Montgomery County 2.36

Illinois 2.62

United States 2.64

Housing Characteristics

Occupied unit characteristics

Tenure, crowding, and utilities

	Montgomery County	Illinois	United States
Total occupied units	11,319	5,036,449	129,227,496
Year moved in
2020 or later	20%	23.3%	24.8%
2010 to 2019	36.5%	38.1%	39.6%
2000 to 2009	17%	17.3%	16.4%
1999 or earlier	26.6%	21.3%	19.1%
Occupants per room
1.00 or fewer	98.1%	97.5%	96.6%
1.01 to 1.50	1%	1.6%	2.2%
1.51 or more	0.9%	0.8%	1.2%
Vehicles availability
No vehicles	6.6%	11%	8.4%
1 vehicle	31.7%	35.7%	33.1%
2 vehicles	36.9%	35.1%	36.6%
3 or more vehicles	24.8%	18.3%	21.9%
House heating fuel used
Gas	72.4%	79.5%	51.4%
Electricity	24.6%	18.6%	41.3%
Solar	0%	0.1%	0.3%
Fuel oil, kerosene etc	0.1%	0.1%	3.9%
All other fuels	2.6%	0.8%	2%
No fuel used	0.3%	0.8%	1.2%
Selected characteristics
Lacking complete plumbing	0.2%	0.3%	0.4%
Lacking complete kitchen	1.3%	0.8%	0.8%
No telephone service available	1.3%	0.8%	0.9%

Housing Value

What owner-occupied units are worth

Median home value

$112,300

owner-occupied units

Median value(USD)

Montgomery County

$112,300

Illinois

$263,300

United States

$332,700

Housing Cost Burden

14.4%

of homeowners with a mortgage are cost-burdened

% Cost-Burdened Households

Owners with a mortgage

14.4%

Owners without a mortgage

15%

Renters

45.6%

Note: Households spending 30% or more of their income on housing costs are considered cost-burdened.

Financial characteristics

Property value and housing costs

Tenure, crowding, and utilities

	Montgomery County	Illinois	United States
Property value
Median Value	$112,300	$263,300	$332,700
Under $100,000	45.4%	13.7%	11.4%
$100,000 - $200,000	29.2%	21.5%	15.8%
$200,000 - $300,000	13.9%	22.3%	17.8%
$300,000 - $500,000	8.7%	27.7%	26.9%
$500,000 - $1,000,000	1.8%	12.1%	20.9%
$1,000,000 and more	1.1%	2.7%	7.1%
Owner-occupied households
With a mortgage	50.6%	60.8%	60.6%
Without a mortgage	49.4%	39.2%	39.4%
Median monthly owner costs
With a mortgage	$1,199	$1,987	$1,963
Without a mortgage	$529	$792	$638
Gross rent
Median rent	$723	$1,274	$1,413

Education Profile

How educated is the community and how education pays off

Adults with a college degree

18.3%

of adults 25+ with a bachelor's degree or higher

Montgomery County 18.3%

Illinois 37.8%

United States 35.7%

Adults without a high school diploma

9.8%

of adults (25+) without a high school diploma

Montgomery County 9.8%

Illinois 9.6%

United States 10.4%

School Enrollment

Who is enrolled in school and at what level

School enrollment

5,592

population (age 3+) enrolled in school

Nursery / Preschool

7.9%

K–12

75.6%

College / Undergraduate

13.1%

Graduate / Professional

3.4%

College-going rate (18-24 yr olds)

18.4%

of 18-24-year-olds in college or graduate school

Montgomery County

18.4%

Illinois

41.4%

United States

40.9%

Enrollment & school type

Enrollment levels, college-going rate, and public vs private school split

Population 3+ currently enrolled in a school

	Montgomery County	Illinois	United States
Total enrolled (age 3+)	5,592	3,051,569	80,089,790
Nursery / preschool	7.9%	6.3%	5.7%
K–12	75.6%	67.3%	67.6%
Kindergarten	8.3%	4.9%	5%
Elementary: Grades 1–4	22.5%	19.5%	19.8%
Elementary: Grades 5–8	20.2%	20.8%	21%
High School: Grades 9–12	24.7%	22.1%	21.7%
College or graduate school	16.5%	26.4%	26.7%
College, undergraduate	13.1%	19.8%	21%
Graduate, professional school	3.4%	6.6%	5.8%
College-going rate · 18-24 yr olds	18.4%	41.4%	40.9%
School type
Public school	92.2%	80.5%	82%
Private school	7.8%	19.5%	18%

Education Attainment by Level & Gender

What is the highest level of education completed among adults

Education attainment

20,365

population 25 years and over

Total adults (25+)

Less than 9th grade

2.2%

9th-12th, no diploma

7.6%

HS graduate

42.1%

Some college no degree

20.5%

Associates degree

9.2%

Bachelors degree

12.1%

Graduate or professional degree

6.2%

Attainment by gender

Male vs Female

Adults (25+) · Share within each education level

% male · % female

Less than 9th grade

67.4% · 32.6%

9th-12th, no diploma

66.1% · 33.9%

HS graduate

56.7% · 43.3%

Some college no degree

53.3% · 46.7%

Associates degree

38.4% · 61.6%

Bachelors degree

48.6% · 51.4%

Graduate or professional degree

39% · 61%

Educational Attainment Overview

Distribution and key education attainment rates for adults (25+)

Highest credential completed · adults 25+

	Montgomery County	Illinois	United States
Population (25+)	20,365	8,767,004	230,807,303
Less than 9th grade	2.2%	4.6%	4.7%
9th–12th, no diploma	7.6%	5%	5.7%
High school diploma or GED	42.1%	25.1%	26%
Some college, no degree	20.5%	19.2%	19.1%
Associate's degree	9.2%	8.3%	8.8%
Bachelor's degree or higher	18.3%	37.8%	35.7%
Bachelor's degree	12.1%	22.6%	21.6%
Graduate or professional	6.2%	15.3%	14.1%
High School or higher	90.2%	90.5%	89.6%

Earnings by education level

percentage as applicable

Median Earnings

$45,598

Median earnings for adults 25+, by level

Less than HS graduate

$35,982

HS graduate

$36,890

Some college or associates

$43,578

Bachelors degree

$55,201

Graduate or professional degree

$72,633

Poverty Rate

4.4%

for ages 25+, with bachelors degree or higher

Less than HS graduate

27.4%

HS graduate

14%

Some college or associates

10.3%

Bachelors degree or higher

4.4%

Outcomes by Education Level

Earnings and poverty rates across education levels (25+)

Adults 25+

	Montgomery County	Illinois	United States
Median earnings
Population 25+, with earnings	$45,598	$55,582	$52,696
Less than high school graduate	$35,982	$34,655	$32,485
High school graduate (includes equivalency)	$36,890	$40,965	$40,153
Some college or associate's degree	$43,578	$47,813	$47,260
Bachelor's degree	$55,201	$73,326	$70,044
Graduate or professional degree	$72,633	$91,623	$90,720
Poverty rates
Less than high school graduate	27.4%	21.6%	24.2%
High school graduate (includes equivalency)	14%	14.4%	14.4%
Some college or associate's degree	10.3%	9.9%	9.8%
Bachelor's degree or higher	4.4%	4.5%	4.5%

Insights for Montgomery County, by topic

Income By year By race By age By gender

Population By year By race By age By gender

About Neilsberg Research

Neilsberg Research team are data scientists with expertise in processing, analysis and visualization of big data helping small businesses make right decisions.

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