Marengo, IL

City in McHenry County, IL, US

By Neilsberg Research

Last updated May 1, 2026

Key Indicators

A quick look at key numbers

Population

7,040

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

Median Age

31.9

years ∙ half population younger than 31.9, half older

Diversity Index

25.9%

chance two random people differ in race and ethnicity

Nativity

5.1%

foreign-born population

94.9%Native

5.1% Foreign-born

Geographic Context

Location, size, and surroundings

About

Marengo is a city within McHenry County, Illinois, United States.

Location

City in McHenry County, IL, US

Co-ordinates

DEC42.246550° N, 88.597500° W

DMS42° 14′ 47.58″ N, 88° 35′ 51.00″ W

Population Density & area

791/sq mi (305.4/km²)

Total Area

8.9 sq mi (23.05 km²)

Land Area

8.9 sq mi (23.05 km²) · 100%

Water Area

0 sq mi (0 km²) · 0%

Demographics & Living

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

Population Composition

Key characteristics of the population

Sex Distribution

52% male

Male 52%

Female 48%

males per 100 females

Marengo 108.2

McHenry County 100.5

Illinois 97.7

Nativity

5.1%

foreign-born population

94.9%Native

5.1% Foreign-born

% Foreign-born

Marengo 5.1%

McHenry County 9.9%

Illinois 14.7%

Age Distribution

How the population is spread across age groups

Median Age

31.9

years ∙ half population younger than 31.9, half older

Marengo

31.9

McHenry County

40.7

Illinois

Dependency ratio

dependents per 100 working-age adults

Marengo 76

McHenry County 64.5

Illinois 63.5

AGE DISTRIBUTION

Distribution of age group

Median age

	Marengo	McHenry County	Illinois
Age Group
Children (Under 18)	26%	22.7%	21.8%
Working age (18-64)	56.8%	60.8%	61.2%
Senior (65+)	17.2%	16.5%	17%
Dependency ratio
Total dependency ratio	76	64.5	63.5
Child dependency ratio	45.7	37.4	35.7
Old-age dependency ratio	30.2	27.1	27.8

Racial & Ethnic Composition

Racial and ethnic makeup and how it compares

Race & Ethnicity

White

85.3%

Black

0.4%

Asian

0.1%

Hispanic

11.3%

Other

2.9%

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

25.9%

chance two random people differ in race and ethnicity

Marengo 25.9%

McHenry County 39.3%

Illinois 60.5%

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 Marengo population

	Marengo	McHenry County	Illinois
Hispanic or Latino	11.3%	16.1%	18.8%
Mexican	9.2%	12.6%	14.4%
Puerto Rican	1%	1.3%	1.6%
Cuban	0%	0.3%	0.3%
Other Hispanic / Latino	1.2%	1.8%	2.5%
Not Hispanic or Latino	88.7%	83.9%	81.2%
One race	85.8%	80.7%	77.8%
White	85.3%	76.1%	58.1%
Black or African American	0.4%	1.4%	13.3%
American Indian and Alaska Native	0%	0%	0.1%
Asian	0.1%	3%	5.9%
Native Hawaiian and Other Pacific Islander	0%	0%	0%
Some Other Race	0%	0.2%	0.4%
Two or more races (Multiracial)	2.9%	3.2%	3.4%

Household & Families Composition

Household size, type, and family structure

Household structure

64% family

Family 64%

Non family 36%

% family households

Marengo 64%

McHenry County 71.9%

Illinois 62.2%

Average household size

2.57

persons per household

Marengo

2.57

McHenry County

2.64

Illinois

2.46

Household & Family COMPOSITION

Households

Percentage of Marengo population

	Marengo	McHenry County	Illinois
Total households	2,719	117,594	5,036,449
Average houshold size	2.57	2.64	2.46
Family households	1,741	84,562	3,130,978
Average family size	3.22	3.13	3.14
Married couple family	1,180	67,264	2,282,435
Other families	561	17,298	848,543
Male householder	67	5,803	248,521
Female householder	494	11,495	600,022
Non-family households	978	33,032	1,905,471
One-person households	835	26,662	1,569,881
Male householder	453	12,619	712,191
Senior (65+) living alone	202	4,589	210,051
Female householder	382	14,043	857,690
Senior (65+) living alone	328	8,200	417,870
Other living arrangements	143	6,370	335,590

Housing Profile

Housing stock, ownership, rentals, and cost burdens

Total housing units

2,788

housing units

Marengo 2,788

McHenry County 121,329

Illinois 5,457,452

Occupancy status

97.5% occupied

Occupied 97.5%

Vacant 2.5%

vacancy rate

Marengo 2.5%

McHenry County 3.1%

Illinois 7.7%

Housing Characteristics

How the housing supply is structured and used

Types of Housing unit

69.7%

Single family houses

69.7%

Apartments in multi-unit structures

22.7%

Mobile homes

7.7%

Boat, RV, van, etc

Median Year Built

1975

Half of houses were built before 1975, and half after.

Historic ∙ 1939 or earlier

21.6%

Postwar & mid-century ∙ 1940 - 1969

25.2%

Late 20th century ∙ 1970 - 1999

33.1%

Modern ∙ 2000 or later

20.1%

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

Housing Characteristics

Units, rooms & bedrooms

Physical characteristics of housing units

	Marengo	McHenry County	Illinois
Rooms per unit
Median rooms	5.6	6.5	5.6
1–3 rooms	6%	6.6%	14.6%
4–6 rooms	61.7%	42.8%	50.9%
7+ rooms	32.3%	50.6%	34.6%
Bedrooms
No bedroom / studio	0.5%	1%	3.1%
1 bedroom	9.5%	5.4%	11.5%
2 bedrooms	35.6%	20.9%	27.7%
3 bedrooms	38.7%	39.8%	35.8%
4+ bedrooms	15.6%	32.9%	21.7%
At a glance
Median year built	1975	1989	1971
Total housing units	2,788	121,329	5,457,452

Occupancy Profile

Who is inside and how they use it

Homeownership

63.1% owners

Renter-occupied 36.9%

Owner-occupied 63.1%

homeownership rate

Marengo 63.1%

McHenry County 82.7%

Illinois 67.1%

Average household size

2.52

Owner-occupied

2.64

Renter-occupied

owner-occupied average size

Marengo 2.52

McHenry County 2.71

Illinois 2.62

Housing Characteristics

Occupied unit characteristics

Tenure, crowding, and utilities

	Marengo	McHenry County	Illinois
Total occupied units	2,719	117,594	5,036,449
Year moved in
2020 or later	18.3%	19.6%	23.3%
2010 to 2019	47%	38.4%	38.1%
2000 to 2009	14.2%	21%	17.3%
1999 or earlier	20.5%	21%	21.3%
Occupants per room
1.00 or fewer	95.6%	98.5%	97.5%
1.01 to 1.50	4.4%	1.2%	1.6%
1.51 or more	0%	0.3%	0.8%
Vehicles availability
No vehicles	3.9%	3.5%	11%
1 vehicle	39.7%	26.5%	35.7%
2 vehicles	29.2%	44%	35.1%
3 or more vehicles	27.2%	26%	18.3%
House heating fuel used
Gas	72.9%	87.6%	79.5%
Electricity	26.6%	11.7%	18.6%
Solar	0%	0.1%	0.1%
Fuel oil, kerosene etc	0%	0%	0.1%
All other fuels	0%	0.3%	0.8%
No fuel used	0.6%	0.3%	0.8%
Selected characteristics
Lacking complete plumbing	0.3%	0.2%	0.3%
Lacking complete kitchen	0.3%	0.5%	0.8%
No telephone service available	0%	0.4%	0.8%

Housing Value

What owner-occupied units are worth

Median home value

$229,900

owner-occupied units

Median value(USD)

Marengo

$229,900

McHenry County

$308,100

Illinois

$263,300

Housing Cost Burden

19.6%

of homeowners with a mortgage are cost-burdened

% Cost-Burdened Households

Owners with a mortgage

19.6%

Owners without a mortgage

39%

Renters

55.1%

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

	Marengo	McHenry County	Illinois
Property value
Median Value	$229,900	$308,100	$263,300
Under $100,000	7.8%	4.1%	13.7%
$100,000 - $200,000	22.8%	14.8%	21.5%
$200,000 - $300,000	46.3%	29%	22.3%
$300,000 - $500,000	22.7%	42.2%	27.7%
$500,000 - $1,000,000	0.4%	9.2%	12.1%
$1,000,000 and more	0%	0.8%	2.7%
Owner-occupied households
With a mortgage	58.4%	68%	60.8%
Without a mortgage	41.6%	32%	39.2%
Median monthly owner costs
With a mortgage	$1,648	$2,137	$1,987
Without a mortgage	$851	$945	$792
Gross rent
Median rent	$1,176	$1,401	$1,274

Education Profile

How educated is the community and how education pays off

Adults with a college degree

15.4%

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

Marengo 15.4%

McHenry County 35.2%

Illinois 37.8%

Adults without a high school diploma

of adults (25+) without a high school diploma

Marengo 5%

McHenry County 6.4%

Illinois 9.6%

School Enrollment

Who is enrolled in school and at what level

School enrollment

1,543

population (age 3+) enrolled in school

Nursery / Preschool

0.8%

K–12

70.9%

College / Undergraduate

25%

Graduate / Professional

3.3%

College-going rate (18-24 yr olds)

42.1%

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

Marengo

42.1%

McHenry County

36.8%

Illinois

41.4%

Enrollment & school type

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

Population 3+ currently enrolled in a school

	Marengo	McHenry County	Illinois
Total enrolled (age 3+)	1,543	74,184	3,051,569
Nursery / preschool	0.8%	5.8%	6.3%
K–12	70.9%	73%	67.3%
Kindergarten	17.8%	5.2%	4.9%
Elementary: Grades 1–4	19.8%	20.1%	19.5%
Elementary: Grades 5–8	11.9%	23%	20.8%
High School: Grades 9–12	21.4%	24.7%	22.1%
College or graduate school	28.3%	21.3%	26.4%
College, undergraduate	25%	16.8%	19.8%
Graduate, professional school	3.3%	4.5%	6.6%
College-going rate · 18-24 yr olds	42.1%	36.8%	41.4%
School type
Public school	91%	87.2%	80.5%
Private school	9%	12.8%	19.5%

Education Attainment by Level & Gender

What is the highest level of education completed among adults

Education attainment

4,409

population 25 years and over

Total adults (25+)

Less than 9th grade

1.9%

9th-12th, no diploma

3.1%

HS graduate

41.7%

Some college no degree

28.3%

Associates degree

9.5%

Bachelors degree

13.2%

Graduate or professional degree

2.2%

Attainment by gender

Male vs Female

Adults (25+) · Share within each education level

% male · % female

Less than 9th grade

42.4% · 57.6%

9th-12th, no diploma

81.5% · 18.5%

HS graduate

56.7% · 43.3%

Some college no degree

39% · 61%

Associates degree

65.8% · 34.2%

Bachelors degree

43.4% · 56.6%

Graduate or professional degree

20.6% · 79.4%

Educational Attainment Overview

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

Highest credential completed · adults 25+

	Marengo	McHenry County	Illinois
Population (25+)	4,409	216,281	8,767,004
Less than 9th grade	1.9%	2.8%	4.6%
9th–12th, no diploma	3.1%	3.6%	5%
High school diploma or GED	41.7%	26.7%	25.1%
Some college, no degree	28.3%	22.4%	19.2%
Associate's degree	9.5%	9.3%	8.3%
Bachelor's degree or higher	15.4%	35.2%	37.8%
Bachelor's degree	13.2%	23.2%	22.6%
Graduate or professional	2.2%	12%	15.3%
High School or higher	95%	93.7%	90.5%

Earnings by education level

percentage as applicable

Median Earnings

$62,132

Median earnings for adults 25+, by level

Less than HS graduate

$30,398

HS graduate

$52,917

Some college or associates

$51,875

Bachelors degree

$77,185

Graduate or professional degree

$110,313

Poverty Rate

for ages 25+, with bachelors degree or higher

Less than HS graduate

57.6%

HS graduate

8.1%

Some college or associates

18.7%

Bachelors degree or higher

Outcomes by Education Level

Earnings and poverty rates across education levels (25+)

Adults 25+

	Marengo	McHenry County	Illinois
Median earnings
Population 25+, with earnings	$62,132	$60,427	$55,582
Less than high school graduate	$30,398	$34,684	$34,655
High school graduate (includes equivalency)	$52,917	$47,168	$40,965
Some college or associate's degree	$51,875	$54,525	$47,813
Bachelor's degree	$77,185	$78,656	$73,326
Graduate or professional degree	$110,313	$94,416	$91,623
Poverty rates
Less than high school graduate	57.6%	14.6%	21.6%
High school graduate (includes equivalency)	8.1%	8.7%	14.4%
Some college or associate's degree	18.7%	4.9%	9.9%
Bachelor's degree or higher	0%	2.2%	4.5%

Insights for Marengo, 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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