Grundy County is located in the U.S. state of Illinois. According to the 2020 census, it has a population of 52,533. Its county seat is Morris.

Grundy County is part of the Chicago metropolitan area.

In 2010, the center of population of Illinois was in Grundy County, just northeast of the village of Mazon.

Illinois's state fossil, the unique and bizarre Tully Monster, was first found in Mazon Creek. Grundy County is home to Dresden Generating Station—the first privately financed nuclear power plant built in the United States—and the Morris Operation—the only de facto high-level radioactive waste storage site in the United States.

History

Grundy County was established on February 17, 1841. It was formed out of LaSalle County and named after U.S. Attorney General Felix Grundy. The county was well known for its coal mines and attracted miners from Pennsylvania and other regions to work its deposits.

The 1883 Diamond Mine Disaster occurred in Grundy County. The disaster took the lives of 69 men and boys who were trapped underground when water broke through into the mine after days of heavy rain and the pumps could not keep up with the rising water. 22 bodies were eventually recovered, the remaining 44 were left in the mine and the mine was sealed. Today a marker stands near where it was believed the majority of victims were entombed.

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File:Grundy County Illinois 1841.png|Grundy County at the time of its creation in 1841

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Geography

According to the U.S. Census Bureau, the county has a total area of , of which is land and (2.9%) is water.

In recent years, average temperatures in the county seat of Morris have ranged from a low of in January to a high of in July, although a record low of was recorded in January 1985 and a record high of was recorded in June 1988. Average monthly precipitation ranged from in February to in June.

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|footnote=U.S. Decennial Census<br />1790-1960 1900-1990<br />1990-2000 2010

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2020 census

As of the 2020 census, the county had a population of 52,533, a median age of 38.7 years, 25.0% of residents were under the age of 18, 15.2% were 65 years of age or older, there were 99.7 males for every 100 females, and there were 96.9 males for every 100 females age 18 and over.

The racial makeup of the county was 85.9% White, 1.6% Black or African American, 0.4% American Indian and Alaska Native, 0.9% Asian, less than 0.1% Native Hawaiian and Pacific Islander, 3.4% from some other race, and 7.8% from two or more races; Hispanic or Latino residents of any race comprised 10.9% of the population.

Seventy-five percent of residents lived in urban areas, while 25.0% lived in rural areas.

There were 20,038 households in the county, of which 34.5% had children under the age of 18 living in them, 53.1% were married-couple households, 17.5% were households with a male householder and no spouse or partner present, 21.9% were households with a female householder and no spouse or partner present, 24.9% were made up of individuals, and 11.0% had someone living alone who was 65 years of age or older.

!Pop 1990

!Pop 2000

!Pop 2010

!style="background-color: #ffffb3;" | Pop 2020

!% 1980

!% 1990

!% 2000

!% 2010

!style="background-color: #ffffb3;" |% 2020

|-

|White alone (NH)

|29,838

|31,433

|35,502

|44,526

|style='background: #ffffe6; |43,472

|97.57%

|97.20%

|94.58%

|88.94%

|style='background: #ffffe6; |82.75%

|-

|Black or African American alone (NH)

|41

|15

|67

|577

|style='background: #ffffe6; |833

|0.13%

|0.05%

|0.18%

|1.15%

|style='background: #ffffe6; |1.59%

|-

|Native American or Alaska Native alone (NH)

|35

|35

|81

|68

|style='background: #ffffe6; |48

|0.11%

|0.11%

|0.22%

|0.14%

|style='background: #ffffe6; |0.09%

|-

|Asian alone (NH)

|108

|105

|112

|318

|style='background: #ffffe6; |466

|0.35%

|0.32%

|0.30%

|0.64%

|style='background: #ffffe6; |0.89%

|-

|Native Hawaiian or Pacific Islander alone (NH)

|x

|x

|2

|12

|style='background: #ffffe6; |16

|x

|x

|0.01%

|0.02%

|style='background: #ffffe6; |0.03%

|-

|Other race alone (NH)

|49

|1

|3

|25

|style='background: #ffffe6; |122

|0.16%

|0.00%

|0.01%

|0.05%

|style='background: #ffffe6; |0.23%

|-

|Mixed race or Multiracial (NH)

|x

|x

|216

|441

|style='background: #ffffe6; |1,864

|x

|x

|0.58%

|0.88%

|style='background: #ffffe6; |3.55%

|-

|Hispanic or Latino (any race)

|511

|748

|1,552

|4,096

|style='background: #ffffe6; |5,712

|1.67%

|2.31%

|4.13%

|8.18%

|style='background: #ffffe6; |10.87%

|-

|Total

|30,582

|32,337

|37,535

|50,063

|style='background: #ffffe6; |52,533

|100.00%

|100.00%

|100.00%

|100.00%

|style='background: #ffffe6; |100.00%

|}

2010 census

As of the 2010 United States census, there were 50,063&nbsp;people, 18,546&nbsp;households, and 13,431&nbsp;families residing in the county. The population density was . There were 19,996 housing units at an average density of . The racial makeup of the county was 93.7% white, 1.2% black or African American, 0.7% Asian, 0.2% American Indian, 2.7% from other races, and 1.5% from two or more races. Those of Hispanic or Latino origin made up 8.2% of the population.

Of the 18,546&nbsp;households, 38.6% had children under the age of 18 living with them, 57.8% were married couples living together, 9.7% had a female householder with no husband present, 27.6% were non-families, and 22.5% of all households were made up of individuals. The average household size was 2.69 and the average family size was 3.16. The median age was 36.1 years.

Communities

right|250px|Map of Grundy County, Illinois.

City

  • Morris

Villages

  • Braceville
  • Carbon Hill
  • Channahon (part)
  • Coal City (part)
  • Diamond (part)
  • Dwight (part)
  • East Brooklyn
  • Gardner
  • Godley (part)
  • Kinsman
  • Mazon
  • Minooka (mostly)
  • Seneca (part)
  • South Wilmington
  • Verona

Former Communities

  • Jugtown

Townships

Grundy County is divided into seventeen townships:

  • Aux Sable
  • Braceville
  • Erienna
  • Felix
  • Garfield
  • Goodfarm
  • Goose Lake
  • Greenfield
  • Highland
  • Maine
  • Mazon
  • Morris
  • Nettle Creek
  • Norman
  • Saratoga
  • Vienna
  • Wauponsee

Unincorporated communities

  • Mazonia
  • Paytonville
  • Nettle Creek
  • Wauponsee

Politics

Grundy County is a Republican stronghold. It has only strayed from voting for Republicans in any election a handful of times. The greatest Democratic margin occurred in 1996, by less than four percent and off the back of Ross Perot's third party candidacy. The county has not voted for a Democratic governor since 1852. Between 1992 and 2012, the margins kept under ten percent, but the Republican favor has increased since Donald Trump.

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Education

K-12 school districts include:

  • Coal City Community Unit School District 1
  • Herscher Community Unit School District 2

Secondary school districts include: