McHenry County , Illinois

McHenry County: County in Illinois, United States

McHenry County locator map
Location of McHenry County on Illinois map.


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 9 years in 2019 county had an estimated population of 307,774 inhabitants. Its county seat is Woodstock. The county was created 185 years ago in 1835.


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.

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The largest city of McHenry County is McHenry with a population of 46,905. Other cities include, Crystal Lake population 39,829, Harvard population 9,060, Marengo population 7,336 and Lakemoor population 5,967. See all McHenry County cities & populated places.

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McHenry County map

McHenry County Quick Facts

Population : 307,774 (2019)
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%
Named for : William McHenry
Altitude : 886 feet / 270 meters
Capital : Woodstock
Establishment : January 01, 1836
Time Zone : America/Chicago
Local time : 09:57:32 (31st July 2021)
Density : 197 Pop. per km² as of 2019
Population growth : -0.32% (2010-2019)

McHenry County has 5 neighbours.


According to census records, the population of McHenry County decreased by 0.32% in 9 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

Comitatul McHenry, Comte de McHenry, Comté de McHenry, Condado de McHenry, Condado han McHenry, Contea di McHenry, Hrabstwo McHenry, Mak-Genri, Makgenri, Makhenri srjan, Makkhenri, McHenry, McHenry Comitatus, McHenry Kun, McHenry Kūn, McHenry konderria, McHenry maakond, McHenry megye, Okrug Makkhenri, Quan McHenry, Quận McHenry, mai ke heng li xian, makuhenri jun, mqatʿt mkhnry, myakahenari ka'unti, Мак-Генри, Макгенрі, Макхенри, Округ Макхенри, Մակհենրի շրջան, مقاطعة مكهنري, مکہنری کاؤنٹی, مکہینری کاؤنٹی، الینوائے, ম্যাকহেনরি কাউন্টি, マクヘンリー郡, 麥克亨利縣

People born in McHenry County (3)

People born in McHenry County, including politician T. V. Eddy, politician M. F. Hatch, politician Frank H. Richards, you can see a list of people who born in McHenry County.

Other places with the same name (1)

McHenry County Populated Places (more)

Cities, Towns, Neighborhoods & Other Populated Places in McHenry County.

City Name Population Title
McHenry 46,905 City in Illinois
Crystal Lake 39,829 City located in McHenry County, Illinois, USA
Algonquin 30,897 Village in Illinois
Lake in the Hills 28,634 Village in Illinois
Huntley 27,228 Village in McHenry and Kane counties, Illinois, United States
Cary 18,067 Village in Illinois, United States
Harvard 9,060 Private research university in Cambridge, Massachusetts, United States
Chemung 8,778 Township in McHenry County, Illinois
Marengo 7,336 City in McHenry County, Illinois, United States
Johnsburg 6,368 Village in United States of America
Lawrence 6,355 Township in Lawrence County, Illinois
Lakemoor 5,967 City in Illinois, United States of America
Spring Grove 5,706 City in Houston County, Minnesota, United States
Fox River Grove 4,573 City in United States of America
Wonder Lake 3,882 Human settlement in Illinois, United States of America
Lakewood 3,843

Illinois Other Counties (more counties)

County Name Population Title
Illinois 12,671,821 State of the United States of America
Cook County 5,150,233 County in Illinois, United States
Chicago 2,693,976 City and county seat of Cook County, Illinois, United States
DuPage County 922,921 County in Illinois, United States
Lake County 696,535 County in Oregon, United States
Will County 690,743 County in Illinois, United States
Kane County 532,403 County in southern Utah, United States
Markham 328,966 City in Cook County, Illinois, United States
Winnebago County 282,572 County in Illinois, United States
Madison County 262,966 County in Montana, United States
Saint Clair County 259,686 The County of St.
Champaign County 209,689 County in Illinois, United States
Sangamon County 194,672 County in Illinois, United States
Peoria County 179,179 County in Illinois, United States of America
McLean County 171,517 County in North Dakota, United States
Rockford 169,980 County seat of Winnebago County, Illinois, United States

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