Grundy County, Illinois

	█ Average max. and min. temperatures in °F
	█ Precipitation totals in inches
	Source: The Weather Channel

Morris, Illinois
Climate chart (explanation)
	█ Average max. and min. temperatures in °F
	█ Precipitation totals in inches
	Source: The Weather Channel
Metric conversion
	█ Average max. and min. temperatures in °C
	█ Precipitation totals in mm

Grundy County
Grundy County
County
	Grundy County Courthouse
	Flag Seal
	Location within the U.S. state of Illinois
	Illinois's location within the U.S.
	Coordinates: 41°17′N 88°26′W / 41.29°N 88.43°W
Country	United States
State	Illinois
Founded	February 17, 1841
Named for	Felix Grundy
Seat	Morris
Largest city	Morris
Area
• Total	430 sq mi (1,100 km2)
• Land	418 sq mi (1,080 km2)
• Water	12 sq mi (30 km2) 2.9%
Population (2020)
• Total	52,533
• Density	120/sq mi (47/km2)
Time zone	UTC−6 (Central)
• Summer (DST)	UTC−5 (CDT)
Congressional district	16th
Website	www.grundyco.org

Grundy County is a county in the U.S. state of Illinois. According to the 2020 census, it has a population of 52,533.^[1] Its county seat is Morris.^[2]

Grundy County is part of the Chicago-Naperville-Elgin, IL-IN-WI Metropolitan Statistical Area.

In 2010, the center of population of Illinois was in Grundy County, just northeast of the village of Mazon.^[3]

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 (1777–1840).^[4] The county was well known for its coal mines^[5] 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.^[6]

Grundy County at the time of its creation in 1841

Geography

According to the U.S. Census Bureau, the county has a total area of 430 square miles (1,100 km²), of which 418 square miles (1,080 km²) is land and 12 square miles (31 km²) (2.9%) is water.^[7]

Climate and weather

In recent years, average temperatures in the county seat of Morris have ranged from a low of 13 °F (−11 °C) in January to a high of 85 °F (29 °C) in July, although a record low of −24 °F (−31 °C) was recorded in January 1985 and a record high of 103 °F (39 °C) was recorded in June 1988. Average monthly precipitation ranged from 1.59 inches (40 mm) in February to 4.16 inches (106 mm) in June.^[8]

Major highways

Adjacent counties

Kendall (north)
Will (east)
Kankakee (southeast)
Livingston (south)
LaSalle (west)

Demographics

Historical population
Census	Pop.	Note	%±
1850	3,023		—
1860	10,379		243.3%
1870	14,938		43.9%
1880	16,732		12.0%
1890	21,024		25.7%
1900	24,136		14.8%
1910	24,162		0.1%
1920	18,580		−23.1%
1930	18,678		0.5%
1940	18,398		−1.5%
1950	19,217		4.5%
1960	22,350		16.3%
1970	26,535		18.7%
1980	30,582		15.3%
1990	32,337		5.7%
2000	37,535		16.1%
2010	50,063		33.4%
2020	52,533		4.9%
2023 (est.)	53,578	^[9]	2.0%
U.S. Decennial Census^[10] 1790-1960^[11] 1900-1990^[12] 1990-2000^[13] 2010^[14]

As of the 2010 United States Census, there were 50,063 people, 18,546 households, and 13,431 families residing in the county.^[15] The population density was 119.8 inhabitants per square mile (46.3/km²). There were 19,996 housing units at an average density of 47.8 per square mile (18.5/km²).^[7] 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.^[15] In terms of ancestry, 28.3% were German, 23.0% were Irish, 12.7% were Italian, 9.4% were Polish, 8.6% were English, 7.1% were Norwegian, and 3.0% were American.^[16]

Of the 18,546 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.^[15]

The median income for a household in the county was $64,297 and the median income for a family was $75,000. Males had a median income of $58,491 versus $36,592 for females. The per capita income for the county was $27,895. About 5.2% of families and 6.9% of the population were below the poverty line, including 8.0% of those under age 18 and 6.5% of those age 65 or over.^[17]

Communities

Townships

Grundy County is divided into seventeen townships:

Unincorporated communities

Politics

United States presidential election results for Grundy County, Illinois^[18]
Year	Republican		Democratic		Third party
Year	No.	%	No.	%	No.	%
2020	16,523	61.75%	9,626	35.98%	607	2.27%
2016	13,454	57.90%	8,065	34.71%	1,718	7.39%
2012	11,343	53.22%	9,451	44.34%	519	2.44%
2008	10,687	48.07%	11,063	49.76%	482	2.17%
2004	11,198	56.47%	8,463	42.68%	170	0.86%
2000	8,709	52.51%	7,516	45.32%	359	2.16%
1996	6,177	41.45%	6,759	45.36%	1,966	13.19%
1992	6,346	39.02%	6,122	37.64%	3,797	23.34%
1988	8,743	60.88%	5,525	38.47%	93	0.65%
1984	9,595	66.98%	4,671	32.61%	59	0.41%
1980	8,397	63.59%	3,970	30.07%	837	6.34%
1976	7,581	57.43%	5,534	41.92%	86	0.65%
1972	8,725	70.70%	3,584	29.04%	32	0.26%
1968	6,607	59.50%	3,407	30.68%	1,091	9.82%
1964	5,522	51.28%	5,246	48.72%	0	0.00%
1960	6,948	61.88%	4,276	38.08%	4	0.04%
1956	7,640	74.46%	2,618	25.51%	3	0.03%
1952	7,347	70.12%	3,118	29.76%	13	0.12%
1948	5,954	64.44%	3,255	35.23%	31	0.34%
1944	6,310	63.89%	3,544	35.88%	22	0.22%
1940	6,593	61.38%	4,105	38.22%	43	0.40%
1936	5,360	52.63%	4,481	44.00%	344	3.38%
1932	4,491	48.21%	4,755	51.05%	69	0.74%
1928	5,126	61.54%	3,174	38.11%	29	0.35%
1924	4,337	63.97%	742	10.94%	1,701	25.09%
1920	4,647	80.05%	803	13.83%	355	6.12%
1916	4,811	66.37%	2,241	30.91%	197	2.72%
1912	1,919	36.41%	1,172	22.24%	2,179	41.35%
1908	3,127	63.08%	1,359	27.42%	471	9.50%
1904	3,448	69.73%	841	17.01%	656	13.27%
1900	3,735	65.50%	1,687	29.59%	280	4.91%
1896	3,246	59.68%	2,074	38.13%	119	2.19%
1892	2,159	50.26%	1,892	44.04%	245	5.70%