McHenry County's 2026 population is estimated at 321,007, reflecting a 0.79% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). McHenry County is the 6th largest county in Illinois. The 2010 population was 309,121 and has grown 3.85% since 2010.
Data after 2023 is projected based on recent change
Overall: 40.7 years
Female: 41.9 years
Male: 39.8 years
There are 241,502 adults, (51,512 of whom are seniors) in McHenry County.
Female: 155,893 (49.9%)
Male: 156,698 (50.1%)
The racial composition of McHenry County includes 79.54% White, 4.59% other race, 3.12% Asian, and smaller percentages for Black or African American, Native American, Native Hawaiian or Pacific Islander and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 248,630 | 79.54% |
| Two or more races | 33,870 | 10.84% |
| Other race | 14,344 | 4.59% |
| Asian | 9,760 | 3.12% |
| Black or African American | 4,755 | 1.52% |
| Native American | 1,185 | 0.38% |
| Native Hawaiian or Pacific Islander | 47 | 0.02% |
McHenry County 's average per capita income is $60,427. Household income levels show a median of $104,802. The poverty rate stands at 6.23%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $138,678 | $166,659 |
| Families | $124,289 | $150,233 |
| Households | $104,802 | $130,520 |
| Non Families | $56,610 | $73,188 |
Average Income
Median Household Income
Poverty Rate
