| Name | Mchenry County |
| State | Illinois |
| FIPS Code | 17111 |
| County Seat | Woodstock |
| Timezone | Central Daylight Time (CDT) |
| Population (2024) | 313,435 |
| Population Growth Rate(2020-2024) | 1% |
| Majority Ethnicity | White 80.19% |
| Public School Majority Ethnicity | White 66% |
| Partisan Voting Index | Republican:+3 |
| Unemployment Rate (May 2026) | 5.2% |
| Sales Tax Rate (2025) | 8.25% |
| Area Code(s) | 815 / 779 / 224 / 847 |
| Race/Ethnicity | Percentage of Population (2023) |
|---|---|
| White | 80.19% |
| African American | 1.52% |
| Hispanic | 15.17% |
| Asian | 2.83% |
| Native American | 0.29% |
| Hawaiin/Pacific Islander | 0.01% |
| Race/Ethnicity | Percentage of Public School Students (2023) |
|---|---|
| White | 65.63% |
| African American | 2.49% |
| Hispanic | 25.33% |
| Asian | 3.37% |
| Native American | 0.32% |
| Hawaiin/Pacific Islander | 0.09% |