McHenry County, Illinois
McHenry County: county in Illinois, United States
About
McHenry County is a county located in the U.S. state of Illinois. As of the 2010 census, the population was 308,760 and a population density of 198 people per km². After 10 years in 2020 county had an estimated population of 305,888 inhabitants. Its county seat is Woodstock. The county was created 190 years ago in 1835.
County Snapshot
McHenry County at a glance
McHenry County currently has 32 quality-checked populated place pages linked on MapSof, making it easier to jump from the county overview into local city pages.
Mapped populated places
32
These counts use a stricter populated-place filter so the main lists stay focused on real city and town pages.
Illinois counties
102
Open related pagesLargest city
Crystal LakePopulation 39,642
Top linked places
Quick Facts about McHenry County
| Population | 305,888 (2020) |
| Country | United States of America |
| State | Illinois (United States) |
| Different from | McHenry County |
| Area | 1563 km2 |
| Water as percent of area | 1.3% |
| Land as percent of area | 98.7% |
| Latitude & Longitude | 42.3244,-88.4525 |
| Named for | William McHenry |
| Altitude | 886 feet / 270 meters |
| Capital | Woodstock |
| Establishment | January 01, 1836 |
| Time Zone | America/Chicago |
| Local time | 11:04:51 (15th April 2026) |
| Density | 196 Pop. per km² as of 2020 |
| Population growth | -0.94% (2010-2020) |
| Weather | 71℉ Chance Showers And Thunderstorms 7-days weather |
Geography
McHenry County is located at 42°19'28"N 88°27'9"W (42.3243900, -88.4524500). It has 5 neighbors: Boone County, Cook County, DeKalb County, Kenosha County and Walworth County.
McHenry County map
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The largest city of McHenry County is Crystal Lake with a population of 39,642. Other cities include, Algonquin population 30,730, Lake in the Hills population 28,345, Huntley population 27,256 and McHenry population 27,100. See all McHenry County cities & populated places.
McHenry County Populated Places (more)
Cities, towns, neighborhoods & other populated places in McHenry County.
| City Name | Population | Title |
|---|---|---|
| Crystal Lake | 39,642 | City located in McHenry County, Illinois, USA |
| Algonquin | 30,730 | Village in Illinois |
| Lake in the Hills | 28,345 | Village in Illinois |
| Huntley | 27,256 | Village in McHenry and Kane counties, Illinois, United States |
| McHenry | 27,100 | City in Illinois |
| Cary | 17,929 | Village in Illinois, United States |
| Harvard | 8,979 | Private research university in Cambridge, Massachusetts, United States |
| Chemung | 8,702 | Township in McHenry County, Illinois |
| Marengo | 7,377 | City in McHenry County, Illinois, United States |
| Johnsburg | 6,310 | Village in United States of America |
| Lakemoor | 5,912 | City in Illinois, United States of America |
| Spring Grove | 5,679 | City in Houston County, Minnesota, United States |
| Fox River Grove | 4,518 | City in United States of America |
| Lawrence | 4,380 | Township in Lawrence County, Illinois |
| Wonder Lake | 3,837 | Human settlement in Illinois, United States of America |
| Pistakee Highlands | 3,454 | Census designated place |
Weather
A chance of showers and thunderstorms. Partly sunny, with a high near 71.
7-Day ForecastOfficial website of McHenry County
Official WebsiteDemographics
According to census records, the population of McHenry County decreased by 0.94% in 10 years.
| Year | Population | % Change | Method |
|---|---|---|---|
| 2010 | 308,760 | - | census |
| 2011 | 308,504 | -0.08% | estimation process |
| 2012 | 308,230 | -0.09% | estimation process |
| 2013 | 307,605 | -0.2% | estimation process |
| 2014 | 307,404 | -0.07% | estimation process |
| 2015 | 307,572 | 0.05% | estimation process |
| 2016 | 307,159 | -0.13% | estimation process |
| 2017 | 307,815 | 0.21% | estimation process |
| 2018 | 308,251 | 0.14% | estimation process |
| 2019 | 307,774 | -0.15% | estimation process |
| 2020 | 305,888 | -0.62% | estimation process |
People born in McHenry County (3)
People born in McHenry County, including politician T. V. Eddy, politician M. F. Hatch, politician Frank H. Richards, .
More notable people
Other places with the same name (1)
- McHenry County, North Dakota county in North Dakota, United States with a population of 5,695 people.
Illinois Other Counties (more counties)
| County Name | Population | Title |
|---|---|---|
| Cook County | 5,108,284 | County in Illinois, United States |
| Chicago | 2,677,643 | The third most populous city in the United States and the center of the Chicago metropolitan area. |
| DuPage County | 917,481 | County in Illinois, United States |
| Lake County | 693,593 | County in Oregon, United States |
| Will County | 688,726 | County in Illinois, United States |
| Kane County | 531,010 | County in southern Utah, United States |
| Winnebago County | 281,295 | County in Illinois, United States |
| Madison County | 262,635 | County in Montana, United States |
| Saint Clair County | 258,046 | The County of St. |
| Champaign County | 209,192 | County in Illinois, United States |
| Aurora | 196,383 | The second most populous city in Illinois. |
| Sangamon County | 193,882 | County in Illinois, United States |
| Peoria County | 177,652 | County in Illinois, United States of America |
| McLean County | 171,256 | County in North Dakota, United States |
| Naperville | 147,986 | The second most populous city in Illinois. |
| Rockford | 144,835 | The second most populous city in Illinois. |