McHenry County is located in the U.S. state of Illinois. According to the 2020 Census, it had a population of 310,229, making it the sixth-most populous county in Illinois. Its county seat is Woodstock. McHenry County is one of the five Illinois collar counties in the Chicago metropolitan area. Long known as a center of recreation along with agriculture in the western portion, it has recently experienced rapid rates of suburbanization, exurbanization and urbanization, but the western segment of the county remains primarily agricultural and rural.
History McHenry County was formed in 1836 out of Cook and LaSalle counties. The county was named for Major William McHenry, a member of the Illinois Militia during Tecumseh's War, a major during the Blackhawk War in 1832, and a member of the Illinois House of Representatives and Senate. He died in Vandalia, Illinois in 1835.
McHenry County originally stretched all the way east to Lake Michigan, with the county seat centrally in McHenry, but in 1839, the eastern townships of the county were carved out forming Lake County.
Historical sites
The Count's House, 3803 Waukegan Rd, McHenry Charles H. Hibbard House, 413 W Grant Hwy, Marengo Col. Gustavus A. Palmer House, 5516 Terra Cotta Rd., Crystal Lake Orson Rogers House, 19621 E Grant Hwy, Marengo Lucein Boneparte Covell House, 5805 Broadway, Richmond Memorial Hall, 10308 Main St, Richmond Old McHenry County Courthouse, Woodstock City Square, Woodstock Woodstock Opera House, 110 Van Buren St, Woodstock Woodstock Square Historic District, Woodstock George Stickney House, 1904 Cherry Valley Rd, Bull Valley Terwilliger House, Mason Hill Rd & Cherry Valley Rd, Bull Valley
Geography According to the U.S. Census Bureau, the county has a total area of , of which is land and (1.3%) is water.
Adjacent counties Walworth County, Wisconsin - north Kenosha County, Wisconsin - northeast Lake County - east Cook County - southeast Kane County - south DeKalb County - southwest Boone County - west
Climate and weather
In recent years, average temperatures in the county seat of Woodstock have ranged from a low of in January to a high of in July, although a record low of was recorded in January 1979 and a record high of was recorded in July 1936. Average monthly precipitation ranged from in February to in June.
McHenry County is like much of the Upper Midwest, as it usually sees hot, humid summers, and cold, snowy winters. The county is notably susceptible to high wind events, blizzards, severe thunderstorms, tornadoes, and flooding.
Some of the most notable weather events in the county include the 1965 Palm Sunday tornado outbreak, the Blizzard of 1967, the 1967 Belvidere - Oak Lawn tornado outbreak, the Blizzard of 1979, the Flood of 1996, the Blizzard of 1999, the Early Winter 2006 North American Storm Complex, the 2007 Midwest flooding event, the January 2008 tornado outbreak sequence, and the Blizzard of 2011.
Demographics
McHenry county has the highest percentage of non-Hispanic whites amongst the five collar counties of Chicago (McHenry, Lake, DuPage, Kane, and Will) as well as Lake County, Indiana which borders Chicago on the east.
Racial and ethnic composition +McHenry County, Illinois – Racial and ethnic compositionRace / Ethnicity (NH = Non-Hispanic)Pop 1980Pop 1990Pop 2000Pop 2010 Pop 2020% 1980% 1990% 2000% 2010% 2020White alone (NH)143,792175,299233,026258,584238,65997.22%95.67%89.60%83.75%76.93%Black or African American alone (NH)1082871,3793,0454,0730.07%0.16%0.53%0.99%1.31%Native American or Alaska Native alone (NH)1452813524553250.10%0.15%0.14%0.15%0.10%Asian alone (NH)5511,2463,7347,7128,6690.37%0.68%1.44%2.50%2.79%Native Hawaiian or Pacific Islander alone (NH)x included in the Asian category in the 1980 Censusx included in the Asian category in the 1990 Census426845xx0.02%0.02%0.01%Other race alone (NH)276621502108720.19%0.03%0.06%0.07%0.28%Mixed race or Multiracial (NH)x not an option in the 1980 Censusx not an option in the 1990 Census1,7923,43710,881xx0.69%1.11%3.51%Hispanic or Latino (any race)3,0256,06619,60235,24946,7052.05%3.31%7.54%11.42%15.06%Total147,897183,241260,077308,760310,229 100.00%100.00%100.00%100.00%100.00%
Racial / Ethnic Profile of places in McHenry County, Illinois (2020 Census)Following is a table of towns and census designated places in NcHenry County, Illinois. Data for the United States (with and without Puerto Rico), the state of Illinois, and McHenry County itself have been included for comparison purposes. The majority racial/ethnic group is coded per the key below. Communities that extend into and adjacent county or counties are delineated with a followed by an accompanying explanatory note. The full population of each community has been tabulated including the population in adjacent counties. Majority minority with no dominant groupMajority WhiteMajority BlackMajority HispanicMajority Asian
+Racial and ethnic composition of places in McHenry County, Illinois (2020 Census) (NH = Non-Hispanic)PlaceDesignationTotal PopulationWhite alone (NH)%Black or African American alone (NH)%Native American or Alaska Native alone (NH)%Asian alone (NH)%Pacific Islander alone (NH)%Other race alone (NH)%Mixed race or Multiracial (NH)%Hispanic or Latino (any race)%United States of America (50 states and D.C.) x331,449,281191,697,64757.84%39,940,33812.05%2,251,6990.68%19,618,7195.92%622,0180.19%1,689,8330.51%13,548,9834.09%62,080,04418.73% x334,735,155191,722,19557.28%39,944,62411.93%2,252,0110.67%19,621,4655.86%622,1090.19%1,692,3410.51%13,551,3234.05%65,329,08719.52% State 12,812,508 7,472,751 58.32% 1,775,612 13.86% 16,561 0.13% 747,280 5.83% 2,959 0.02% 45,080 0.35% 414,855 3.24% 2,337,410 18.24% County 310,229 238,659 76.93% 4,073 1.31% 325 0.10% 8,669 2.79% 45 0.01% 872 0.28% 10,881 3.51% 46,705 15.06% Alden CDP 113 102 90.27% 0 0.00% 0 0.00% 0 0.00% 0 0.00% 1 0.88% 5 4.42% 5 4.42% Algonquin partly in Kane County Village 29,700 22,327 75.18% 704 2.37% 27 0.09% 2,143 7.22% 7 0.02% 85 0.29% 1,048 3.53% 3,359 11.31% Barrington Hills majority in Cook County but also Kane, McHenry and Lake counties Village 4,114 3,369 81.89% 39 0.95% 4 0.10% 348 8.46% 0 0.00% 18 0.44% 124 3.01% 212 5.15% Big Foot Prairie CDP 65 28 43.08% 0 0.00% 0 0.00% 1 1.54% 0 0.00% 0 0.00% 2 3.08% 34 52.31% Bull Valley Village 1,128 1,002 88.83% 2 0.18% 2 0.18% 17 1.51% 0 0.00% 1 0.09% 46 4.08% 58 5.14% Burtons Bridge CDP 226 170 75.22% 9 3.98% 0 0.00% 2 0.88% 1 0.44% 2 0.88% 8 3.54% 34 15.04% Cary Village 17,826 14,417 80.88% 134 0.75% 25 0.14% 516 2.89% 4 0.02% 52 0.29% 8 0.04% 2,100 11.78% Chemung CDP 276 179 64.86% 0 0.00% 0 0.00% 0 0.00% 0 0.00% 1 0.36% 6 2.17% 90 32.61% Coral CDP 16 10 62.50% 0 0.00% 0 0.00% 0 0.00% 0 0.00% 0 0.00% 0 0.00% 6 37.50% Crystal Lake City 40,269 30,976 76.92% 586 1.46% 37 0.09% 1,091 2.71% 3 0.01% 147 0.37% 1,474 3.66% 5,955 14.79% Fox Lake mostly in Lake County Village 10,978 8,748 79.69% 219 1.99% 15 0.14% 134 1.22% 4 0.04% 16 0.15% 456 4.15% 1,386 12.63% Fox River Grove partly in Lake County Village 4,702 3,866 82.22% 36 0.77% 3 0.06% 188 4.00% 0 0.00% 18 0.38% 202 4.30% 389 8.27% Franklinville CDP 38 33 86.84% 0 0.00% 0 0.00% 0 0.00% 0 0.00% 0 0.00% 4 10.53% 1 2.63% Greenwood Village 324 258 79.63% 2 0.62% 1 0.31% 1 0.31% 0 0.00% 1 0.31% 9 2.78% 52 16.05% Harmony CDP 20 14 70.00% 0 0.00% 0 0.00% 0 0.00% 0 0.00% 0 0.00% 3 15.00% 3 15.00% Hartland CDP 157 126 80.25% 4 2.55% 0 0.00% 0 0.00% 0 0.00% 4 2.55% 6 3.82% 17 10.83% Harvard City 9,469 3,885 41.03% 55 0.58% 4 0.04% 75 0.79% 0 0.00% 17 0.18% 219 2.31% 5,214 55.06% Hebron Village 1,368 1,067 78.00% 7 0.51% 1 0.07% 2 0.15% 0 0.00% 6 0.44% 47 3.44% 238 17.40% Holiday Hills Village 618 509 82.36% 1 0.16% 0 0.00% 1 0.16% 0 0.00% 1 0.16% 28 4.53% 78 12.62% Huntley partly in Kane County Village 27,740 22,223 80.11% 450 1.62% 24 0.09% 1,516 5.47% 1 0.00% 60 0.22% 883 3.18% 2,583 9.31% Island Lake partly in Lake County Village 8,051 6,137 76.23% 96 1.19% 10 0.12% 159 1.97% 1 0.01% 21 0.26% 299 3.71% 1,328 16.49% Johnsburg Village 6,355 5,684 89.44% 22 0.35% 6 0.09% 54 0.85% 0 0.00% 10 0.16% 253 3.98% 326 5.13% Lake in the Hills Village 28,982 20,856 71.96% 659 2.27% 32 0.11% 1,637 5.65% 9 0.03% 88 0.30% 996 3.44% 4,705 16.23% Lakemoor partly in Lake County Village 6,182 4,568 73.89% 149 2.41% 6 0.10% 166 2.69% 0 0.00% 20 0.32% 241 3.90% 1,032 16.69% Lakewood Village 4,283 3,699 86.36% 25 0.58% 7 0.16% 153 3.57% 0 0.00% 9 0.21% 178 4.16% 212 4.95% Lawrence CDP 220 159 72.27% 6 2.73% 0 0.00% 2 0.91% 0 0.00% 0 0.00% 11 5.00% 42 19.09% Marengo City 7,568 5,758 76.08% 94 1.24% 20 0.26% 51 0.67% 0 0.00% 16 0.21% 248 3.28% 1,381 18.25% McCullom Lake Village 988 750 75.91% 7 0.71% 0 0.00% 16 1.62% 0 0.00% 0 0.00% 49 4.96% 166 16.80% McHenry City 27,135 21,144 77.92% 280 1.03% 20 0.07% 493 1.82% 4 0.01% 40 0.15% 954 3.52% 4,200 15.48% Oakwood Hills Village 2,076 1,731 83.38% 15 0.72% 4 0.19% 29 1.40% 3 0.14% 13 0.63% 93 4.48% 188 9.06% Pistakee Highlands CDP 3,237 2,805 86.65% 22 0.68% 6 0.19% 18 0.56% 0 0.00% 6 0.19% 123 3.80% 257 7.94% Port Barrington partly in Lake County Village 1,584 1,257 79.36% 17 1.07% 2 0.13% 99 6.25% 1 0.06% 5 0.32% 44 2.78% 159 10.04% Prairie Grove Village 1,963 1,698 86.50% 12 0.61% 3 0.15% 84 4.28% 0 0.00% 11 0.56% 50 2.55% 105 5.35% Richmond Village 2,089 1,798 86.07% 29 1.39% 1 0.05% 28 1.34% 0 0.00% 4 0.19% 72 3.45% 157 7.52% Ridgefield CDP 210 193 91.90% 0 0.00% 0 0.00% 0 0.00% 1 0.48% 0 0.00% 2 0.95% 14 6.67% Riley CDP 10 8 80.00% 0 0.00% 0 0.00% 0 0.00% 0 0.00% 0 0.00% 1 10.00% 1 10.00% Ringwood Village 844 741 87.80% 12 1.42% 0 0.00% 6 0.71% 0 0.00% 0 0.00% 39 4.62% 46 5.45% Solon Mills CDP 133 111 83.46% 0 0.00% 1 0.75% 0 0.00% 0 0.00% 0 0.00% 10 7.52% 11 8.27% Spring Grove Village 5,487 4,955 90.30% 22 0.40% 4 0.07% 47 0.86% 0 0.00% 7 0.13% 174 3.17% 278 5.07% Trout Valley Village 515 466 90.49% 3 0.58% 2 0.39% 2 0.39% 0 0.00% 0 0.00% 18 3.50% 24 4.66% Union Village 551 481 87.30% 0 0.00% 0 0.00% 6 1.09% 0 0.00% 0 0.00% 16 2.90% 48 8.71% Wonder Lake Village 3,973 3,301 83.09% 26 0.65% 11 0.28% 30 0.76% 2 0.05% 11 0.28% 137 3.45% 455 11.45% Woodstock City 25,630 16,456 64.21% 737 2.88% 33 0.13% 527 2.06% 2 0.01% 106 0.41% 860 3.36% 6,909 26.96%
2020 census
As of the 2020 census, the county had a population of 310,229, a median age of 40.8 years, and 23.0% of residents under the age of 18 while 15.6% were 65 years of age or older. For every 100 females there were 98.9 males, and for every 100 females age 18 and over there were 97.2 males age 18 and over.
The racial makeup of the county was 79.9% White, 1.4% Black or African American, 0.5% American Indian and Alaska Native, 2.8% Asian, less than 0.1% Native Hawaiian and Pacific Islander, 6.3% from some other race, and 9.1% from two or more races, with Hispanic or Latino residents of any race comprising 15.1% of the population.
Eighty-five point nine percent of residents lived in urban areas, while 14.1% lived in rural areas.
There were 114,282 households in the county, of which 33.4% had children under the age of 18 living in them, 58.0% were married-couple households, 14.8% were households with a male householder and no spouse or partner present, and 20.6% were households with a female householder and no spouse or partner present.
About 21.7% of all households were made up of individuals and 9.5% had someone living alone who was 65 years of age or older. There were 119,708 housing units, of which 4.5% were vacant, 80.7% of occupied units were owner-occupied, and 19.3% were renter-occupied, with a homeowner vacancy rate of 1.4% and a rental vacancy rate of 5.6%.
2010 census