McHenry County, Illinois: Diversifying Metro county. In 2024, voted R+5%. Republican peak: R+72 in 1920.
Key facts
- 2024 presidential margin
- R+5MIT Election Lab
- Political typology
- Diversifying MetroAkashic typology
- Population
- 312,5912024 5-year
- Median household income
- $104,8022024 5-year
- White (non-Hispanic)
- 79.5%2024 5-year
- Black
- 1.5%2024 5-year
- Hispanic / Latino
- 16.1%2024 5-year
- Peak Democratic margin
- D+5 in 2008MIT Election Lab
- Peak Republican margin
- R+72 in 1920MIT Election Lab
- Most similar
- Kendall County, IL · similarity 0.97
2024 results by precinct
2024 precinct map of McHenry CountyPrecinct-level 2024 presidential results for McHenry County, with each precinct boundary colored by Democratic-vs-Republican margin.
—
Margin—
Turnout—
Harris +50Trump +50
Real precinct boundaries. Hover for vote totals.
presidential history
Presidential margin, 1876–2024
Democratic minus Republican, by election
| Year | Margin (D minus R) |
|---|---|
| 1876 | No data |
| 1880 | No data |
| 1884 | No data |
| 1888 | No data |
| 1892 | −15.4% |
| 1896 | −44.0% |
| 1900 | −42.3% |
| 1904 | −58.5% |
| 1908 | −45.9% |
| 1912 | −6.1% |
| 1916 | −45.9% |
| 1920 | −71.9% |
| 1924 | −56.7% |
| 1928 | −31.0% |
| 1932 | −8.7% |
| 1936 | −25.9% |
| 1940 | −45.2% |
| 1944 | −47.4% |
| 1948 | −47.4% |
| 1952 | −48.7% |
| 1956 | −56.9% |
| 1960 | −34.1% |
| 1964 | −11.1% |
| 1968 | −39.7% |
| 1972 | −49.7% |
| 1976 | −36.9% |
| 1980 | −41.4% |
| 1984 | −53.0% |
| 1988 | −41.6% |
| 1992 | −18.8% |
| 1996 | −11.9% |
| 2000 | −20.2% |
| 2004 | −20.4% |
| 2008 | +5.3% |
| 2012 | −8.8% |
| 2016 | −7.5% |
| 2020 | −2.5% |
| 2024 | −5.3% |
DemocraticRepublican
38 presidential elections
| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| R | 75,370 | 83,933 | 162,283 | ||
| R | 78,154 | 82,260 | 164,578 | ||
| R | 60,803 | 71,612 | 143,930 | ||
| R | 59,797 | 71,598 | 134,237 | ||
| D | 72,288 | 64,845 | 139,268 | ||
| R | 50,330 | 76,412 | 127,948 | ||
| R | 40,698 | 62,112 | 106,185 | ||
| R | 31,240 | 41,136 | 83,256 | ||
| R | 24,783 | 41,356 | 88,294 | ||
| R | 18,919 | 46,135 | 65,499 | ||
| R | 14,420 | 47,282 | 62,042 | ||
| R | 14,540 | 40,045 | 61,655 | ||
| R | 16,799 | 37,115 | 54,989 | ||
| R | 12,090 | 36,114 | 48,312 | ||
| R | 10,896 | 27,245 | 41,185 | ||
| R | 18,014 | 22,503 | 40,517 | ||
| R | 12,659 | 25,787 | 38,508 | ||
| R | 6,820 | 24,912 | 31,798 | ||
| R | 7,218 | 20,975 | 28,257 | ||
| R | 5,459 | 15,387 | 20,949 | ||
| R | 5,567 | 15,666 | 21,299 | ||
| R | 6,170 | 16,480 | 22,795 | ||
| R | 6,893 | 12,031 | 19,866 | ||
| R | 8,260 | 9,880 | 18,594 | ||
| R | 5,596 | 10,661 | 16,319 | ||
| R | 1,372 | 8,751 | 13,015 | ||
| R | 1,536 | 9,885 | 11,616 | ||
| R | 3,278 | 9,024 | 12,532 | ||
| O | 1,913 | 2,370 | 7,447 | ||
| R | 1,887 | 5,331 | 7,501 | ||
| R | 1,309 | 5,409 | 7,006 | ||
| R | 2,076 | 5,234 | 7,468 | ||
| R | 1,913 | 5,047 | 7,117 | ||
| R | 2,311 | 3,205 | 5,810 | ||
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Demographics
2024 ACS
Race, ethnicity, and ancestry
Click any group to see the ancestries typically reported within it.
German
26.7%
Irish
15.8%
Polish
10.8%
Italian
9.4%
English
8.2%
American
2.8%
French
1.7%
African American
1.2%
Multiple ancestry combinations reported; no single grouping above 1%.
American Indian, Alaska Native, Native Hawaiian, and Pacific Islander combined.
Source · American Community Survey 5-year estimates, 2024 release. Hispanic/Latino is an ethnicity that overlaps the race categories, so these shares can total more than 100%. Ancestry is a self-reported, multiple-response item; ancestry percentages do not sum to the parent race percentage.
2024 ACS
Age distribution by sex
Median age: 40.7 in this county, 39.1 nationally
Male
Age
Female
85+
75–84
65–74
55–64
45–54
35–44
25–34
18–24
5–17
<5
Source · American Community Survey 5-year estimates, 2024 release.
2024 ACS
Median household income
Inflation-adjusted dollars
$104,802
McHenry County ranks in the top 5% of US counties.
McHenry County$104,802
Illinois$83,390
United States$80,734
McHenry County ranks in the top 5% of US counties by median household income.
Source · American Community Survey 5-year estimates, 2024 release.
2024 ACS
Poverty rate
All persons below federal poverty line
6.2%
Child poverty is below the national average.
Children under 188.2%
Working age (18–64)5.4%
Seniors (65+)8.7%
Source · American Community Survey 5-year estimates, 2024 release.
2024 ACS
Language at home
Population aged 5 and older
83.9%
speak English only
Spanish10.6%
Other Indo-European3.9%
Asian & Pacific Islander1.3%
Other languages0.3%
Source · ACS 5-year estimates, 2024.
2020 religion census
Religious adherents
Adherents per capita by tradition
Source · 2020 US Religion Census. Remaining 61.6% of residents not counted as adherents by any reporting body.
A fast-growing exurban county northwest of Chicago, McHenry shifted from R+20 margins a decade ago to R+5.3 in 2024, reflecting the broader realignment of college-educated suburban voters across the collar counties.
The Democratic margin here reached five points in 2008. Between 2020 and 2024 the county moved three points toward the Republican candidate; the 2024 margin was five points.
A population of 312,591, a 80% non-Hispanic-white share, and a median household income of $104,802 describe the county. The county's voting pattern over the last decade is most similar to that of Kendall County and Seminole County.
Most similar counties
Compare two places, side by side
Twelve curated comparisons line up election history, demographics, and the divergence story for two places at a glance. Browse all comparisons →
Cite this page
All citations released under CC BY 4.0. Attribution: Akashic Intelligence.
McHenry County, Illinois. Akashic. https://akashic.app/county/17111/. Accessed May 20, 2026. License: CC BY 4.0.
License: CC BY 4.0
More diversifying metro counties
Frequently asked questions
How did McHenry County, Illinois vote in 2024?
In 2024, McHenry County, Illinois voted Republican by 5.3 points (R+5), carried by the Republican candidate. Out of 162,283 votes cast, 75,370 went Democratic and 83,933 went Republican.
What is McHenry County, Illinois's political typology?
Akashic places McHenry County, Illinois in the "Diversifying Metro" typology — Mid-size metropolitan counties growing more diverse and trending Democratic. The typology is a data-driven cluster built from vote share, vote swing, race and ethnicity, income, language spoken at home, religion, and ancestry. Across 38 elections in the dataset, the county has voted Democratic 1 times, Republican 32 times, and other 1 times.
When did McHenry County, Illinois last vote Democratic?
The most recent presidential election in which McHenry County, Illinois voted Democratic was 2008.
How many people live in McHenry County, Illinois?
McHenry County, Illinois has a population of 312,591 according to the 2024 American Community Survey 5-year estimates from the US Census Bureau.
What is the median household income in McHenry County, Illinois?
Median household income in McHenry County, Illinois is $104,802 — above the national median of $80,734. The Illinois state median is $83,390.
What is the political history of McHenry County, Illinois?
Akashic tracks 38 presidential elections in McHenry County, Illinois from 1876 to 2024. Of those, 1 went Democratic and 32 went Republican. The county's typology — "Diversifying Metro" — captures where that record, its demographics, and its recent swing place it among American communities.