• county
  • FIPS 17111
  • Largest town: Crystal Lake

McHenry County, Illinois

McHenry County had 315,959 residents in the Census Vintage 2024 estimate, on 603.4 square miles of land. It ranks 6th of 102 in Illinois by population and 34th by land area.

Population
315,959
#6 of 102 in Illinois · #234 in US
Area
603.4 sq mi
#34 of 102 in Illinois · #1,616 in US
Density
524 / sq mi
#7 of 102 in Illinois · #271 in US
Median household income
$101,205
#6 of 102 in Illinois · #125 in US

Census Vintage 2024 estimates · SAIPE 2023 income · 2024 Gazetteer land area

McHenry County within Illinois. Pin: Springfield.

Measure from here

Tools and pages that start from McHenry County

McHenry County population, land area and income

McHenry County had 315,959 residents in the Census Vintage 2024 estimate, on 603.4 square miles of land. It ranks 6th of 102 in Illinois by population and 34th by land area. That works out to 523.6 people per square mile, 5.4 times the US average of 96.3, and in the top tenth nationally.

The median county-equivalent in Illinois has 24,447 residents, so McHenry County is 12.9 times that size.

Its SAIPE 2023 median household income of $101,205 is in the top tenth among 3,143 counties with an estimate.

National rank among 3,144

Population

315,959

3144th1st

234th of 3,144 (US)

Land area

603 sq mi

3144th1st

1616th of 3,144 (US)

Density

523.6 / sq mi

3144th1st

271st of 3,144 (US)

Median household income

$101,205

3143rd1st

125th of 3,143 (US)

Rank within Illinois (102)

Population

315,959

102nd1st

6th of 102 (IL)

Land area

603 sq mi

102nd1st

34th of 102 (IL)

Density

523.6 / sq mi

102nd1st

7th of 102 (IL)

Median household income

$101,205

102nd1st

6th of 102 (IL)

How McHenry County's population changed since 2020

McHenry County gained 5,986 residents between the July 2020 and July 2024 estimates, a rise of 1.9%. That ranks 4th of 102 in Illinois for growth. The median Illinois county changed by -1.7%, and the state as a whole by -0.7%.

Since the April 2020 estimates base, McHenry County recorded 13,114 births and 10,835 deaths, a natural change of +2,279. Net international migration added +1,325 and net domestic migration, people moving to or from other US counties, came to +1,996. The largest single component was natural change, which added 2,279 people.

310.0k2020311.7k2021311.9k2022313.4k2023316.0k2024
Census Vintage 2024 county estimates for July 1 of each year. The axis starts above zero so year-to-year changes are visible.

Components of change, April 2020 to July 2024

Births
13,114
Deaths
10,835
Net international migration
+1,325
Net domestic migration
+1,996
Change, July 2023 to July 2024
+2,524

Where McHenry County is

The Census internal point of McHenry County is at 42.324300, -88.452200. It sits in UTM zone 16N. The map shades Illinois's 102 county-equivalents by population change from 2020 to 2024, darker for faster growth, with McHenry County outlined. Dots are towns of 1,000+ people with residents in it.

Piatt County: -0.3%Hamilton County: -2.2%Williamson County: -0.1%Edgar County: -2.4%Macoupin County: -2.3%Marshall County: -1.3%Putnam County: +0.0%Richland County: -2.8%Washington County: -1.4%Lee County: -1.5%Douglas County: +0.2%Cook County: -1.6%Effingham County: -0.3%Edwards County: -3.6%Cass County: -2.0%Clay County: -3.4%Knox County: -2.2%LaSalle County: -0.9%Cumberland County: -1.3%Warren County: -3.7%Moultrie County: -0.9%Menard County: -2.5%Fayette County: -1.5%Boone County: -0.0%Lawrence County: -3.2%Marion County: -3.2%Champaign County: +3.0%Clark County: -2.4%Ford County: -0.4%Wayne County: -1.4%Logan County: -1.4%Grundy County: +2.5%Jasper County: -1.8%Crawford County: -1.3%McDonough County: -1.7%Clinton County: +0.5%Perry County: -3.0%Montgomery County: -2.2%Henry County: -2.0%Livingston County: -1.2%Scott County: -3.8%Alexander County: -11.2%Bureau County: -2.2%Brown County: +1.1%Mason County: -3.9%Calhoun County: -4.1%Greene County: -4.3%Coles County: -1.4%Kendall County: +8.2%Lake County: +0.7%Mercer County: -2.2%St. Clair County: -2.3%Wabash County: -3.0%Bond County: -1.7%DuPage County: +0.6%Gallatin County: -5.2%Stephenson County: -3.3%McHenry County: +1.9%White County: -3.0%Saline County: -3.9%Christian County: -2.2%Sangamon County: -1.0%Massac County: -3.6%Macon County: -2.9%Johnson County: -0.0%Jo Daviess County: -2.6%Peoria County: -1.0%DeKalb County: +1.0%Pope County: -1.5%De Witt County: -0.9%Schuyler County: -1.7%Fulton County: -3.1%Ogle County: -0.8%Jersey County: -1.6%Iroquois County: -3.3%Kankakee County: -0.9%Rock Island County: -1.1%Pulaski County: -5.8%Kane County: +0.9%Union County: -2.4%Whiteside County: -1.7%Woodford County: -0.3%Carroll County: -1.5%Adams County: -2.3%Hardin County: -2.6%Madison County: -1.0%Hancock County: -3.1%Monroe County: +0.0%Tazewell County: -1.1%Jackson County: -0.1%Vermilion County: -3.9%Randolph County: -0.6%McLean County: +0.5%Morgan County: -2.6%Shelby County: -1.7%Will County: +1.7%Winnebago County: -0.4%Jefferson County: -2.4%Stark County: -2.2%Henderson County: -4.5%Pike County: -2.6%Franklin County: -1.8%
Change 2020 to 2024
  1. < -3.0%
  2. < -2.2%
  3. < -1.4%
  4. < -0.3%
  5. ≥ -0.3%
no data

Orange pin: McHenry County internal point. Dark pin: Springfield.

Internal point

Decimal
42.324300, -88.452200
DMS
42°19'27.48"N 88°27'7.92"W
UTM
16N 380343.6E 4686805.0N
Geohash
dp90g0zhf
Plus code
86JH8GFX+P4

Towns in McHenry County

24 incorporated places of 1,000+ people have residents in McHenry County, 249,575 people together, or 79% of the county. Each figure counts only the part of the town inside McHenry County; towns marked "part" extend into another county. The largest is Crystal Lake with 41,513.

  1. 01Crystal Lake41,513
  2. 02McHenry28,825
  3. 03Lake in the Hills28,706
  4. 04Woodstock25,892
  5. 05Huntley (part)22,679
  6. 06Algonquin (part)22,139
  7. 07Cary18,031
  8. 08Harvard9,408
  9. 09Marengo7,699
  10. 10Johnsburg6,428
  11. 11Spring Grove5,554
  12. 12Wonder Lake5,296
  13. 13Island Lake (part)4,698
  14. 14Lakewood4,287
  15. 15Fox River Grove (part)4,255
Census Vintage 2024 subcounty estimates, county parts of incorporated places (SUMLEV 157).

Counties bordering McHenry County

The Census 2024 county adjacency file lists 7 neighbors for McHenry County, including 2 across a state line. The most populous is Cook County, IL, with 5,182,617 residents. Distances run between Census internal points in a straight line.

Distance to Springfield and the nearest big city

Springfield is 186.5 miles SSW of McHenry County's internal point in a straight line. The nearest place of 100,000 or more is Elgin, IL (population 114,701), 20.8 miles away. The nearest place of 10,000 or more is Woodstock, IL (population 25,892), 1.4 miles away.

McHenry County FIPS code

The FIPS code of McHenry County is 17111: state code 17 for Illinois plus county code 111. Use it as text, with the leading zero, when joining Census, BLS, or CDC county tables. SAIPE lists its 2023 median household income as $101,205.

Questions people ask

What is the population of McHenry County, Illinois?

The Census Vintage 2024 estimate for July 1, 2024 is 315,959. That is up 5,986 people (1.9%) from the July 2020 estimate of 309,973.

What is the FIPS code of McHenry County?

17111. The first two digits (17) are Illinois; the last three (111) identify the county.

What is the largest town in McHenry County?

Crystal Lake, with 41,513 residents inside McHenry County in 2024.

Which counties border McHenry County?

7 county-equivalents border it in the Census 2024 adjacency file: Cook County, IL; Lake County, IL; Kane County, IL; Kenosha County, WI; Walworth County, WI; DeKalb County, IL; Boone County, IL.

Sources and data as of

Data as of: Census Vintage 2024 population estimates, 2024 Gazetteer land area and internal points, SAIPE 2023 median household income.

  1. 01Census Vintage 2024 county population estimates
  2. 02Census 2024 Gazetteer, counties
  3. 03Census SAIPE 2023 state and county estimates
  4. 04Census Vintage 2024 subcounty population estimates
  5. 05Census 2024 county adjacency file
  6. 06Census 2024 cartographic boundary file, counties (1:5,000,000)

How every number is computed: methodology. Spotted a wrong figure? Report an error.