What is the largest city in McHenry County, IL?

Crystal Lake is the largest city or town in McHenry County, with about 40,579 residents.

How many ZIP codes are in McHenry County?

McHenry County includes 19 ZIP Code Tabulation Areas, including 60012, 60013, 60014, 60021, 60033.

What is the population of McHenry County, IL?

About 312,591 people live in McHenry County, based on American Community Survey 5-year estimates.

What counties border McHenry County?

McHenry County borders Cook County, Lake County, Kane County, Kenosha County, WI, Walworth County, WI, DeKalb County, Boone County.

McHenry County, IL: Cities, ZIP Codes & Local Data

Population

312,591

Land area

603sq mi

People per sq mi

518

ZIP codes

19

McHenry County at a glance

McHenry County is about 2.3 times as dense as Illinois as a whole.
It is the 6th most populous of 102 counties in Illinois.
Households here earn a median of $104,802 a year, 26% more than the Illinois figure of $83,390.
A typical owner-occupied home is valued at $308,100 (17% above Illinois) and median rent is $1,401 a month.
The biggest population centers are Crystal Lake (40,579), Algonquin (30,067) and Lake in the Hills (28,800).

Local data for McHenry County, IL

Counts from official public data

Housing and community stats

McHenry County, IL, American Community Survey 2020-2024

Full profile

Median household income

$104,802

Poverty rate

6.2%

Median home value

$308,100

Prices +5.8% in a year

Median rent

$1,401/mo

Homeownership

82.7%

Bachelor's or higher

35.2%

Median age

40.7

Average commute

30.1 min

Largest reported origins and ancestries: German Americans (83,320), Irish Americans (49,359), Mexican Americans (39,343).

Home values and rents Income, education and commute

Economy and federal money

Jobs, income, federal spending and pandemic loans

Details

Unemployment rate

3.8%

Sep 2026, +0.4 pts in a year

Average annual pay

$57,103

98,058 jobs, 2025

Income per person

$72,162

BEA, 2024

Federal spending

$1.9B

FY 2026, $6,123 per person

PPP loans

$691M

9,599 loans, 76,925 jobs reported

Campaign donations

$1.3M

Itemized, 2026 cycle

Economy Federal spending PPP loans

How people get to work

McHenry County, IL, workers 16 and older. American Community Survey 5-year estimates

Drove alone72.9%
Carpooled7.7%
Public transit1.3%
Walked1.1%
Bicycle0.1%
Taxi, ride-hailing, motorcycle or other0.8%
Worked from home16.1%

Average one-way commute: 30.1 minutes for people who do not work from home.

Environment and hazard risk

McHenry County, IL, from FEMA, NOAA and EPA

Full report

Natural hazard risk

Relatively Moderate

Top: cold wave

Storm events since 1996

783

Most often thunderstorm wind

Flood insurance policies

764

0.7% of homes, county

July high / Jan low

84° / 14°F

39.3 inches of rain a year

Hazards, floods and storm history Check a flood zone 11 historic places

Health statistics

Share of adults in McHenry County, IL, CDC PLACES estimates

All 40 measures

Obesity

32.1%

U.S. 33.3% -1.2 pts

Diabetes

10.5%

U.S. 12.1% -1.6 pts

Smoking

11.5%

U.S. 12.8% -1.3 pts

Uninsured (18-64)

7.9%

U.S. 11.1% -3.2 pts

Cities, towns and ZIP codes in McHenry County

Population shown

Frequently asked questions

What is the largest city in McHenry County, IL?: Crystal Lake is the largest city or town in McHenry County, with about 40,579 residents.
How many ZIP codes are in McHenry County?: McHenry County includes 19 ZIP Code Tabulation Areas, including 60012, 60013, 60014, 60021, 60033.
What is the population of McHenry County, IL?: About 312,591 people live in McHenry County, based on American Community Survey 5-year estimates.
What counties border McHenry County?: McHenry County borders Cook County, Lake County, Kane County, Kenosha County, WI, Walworth County, WI, DeKalb County, Boone County.