Township · Illinois
Big Rock Township, Illinois
Big Rock Township, township, in Kane County, Illinois. Big Rock Township had 1,739 residents on July 1, 2025 by the Census Bureau's estimate, down 2.2% since 2020; the 2020 Census counted 1,768 and the ACS 2020-2024 5-year estimates put it at 2,110 (±578). GEOID 1708905989.
Residents, July 2025 estimate
1,739
Census Bureau estimate (no margin published)
2020 Census count: 1,768 · ACS 2020-2024: 2,110 ±578
Median household income
$158,250
±$51,214 (90% margin)
Illinois: $83,390
Median home value
$336,400
±$23,079 (90% margin)
Illinois: $263,300
Median gross rent
$1,653
±$175 (90% margin)
Illinois: $1,274
Where is Big Rock Township and what county is it in?
Big Rock Township is a township in Kane County, Illinois. It covers 35.1 square miles of land, 50 residents per square mile in 2020.
One place lies inside Big Rock Township: Big Rock (village, 1,104 in 2020). Part of Sugar Grove (village) also lies in it.
Big Rock Township is in the Chicago-Naperville-Elgin, IL-IN metropolitan statistical area, which takes in 13 counties (Census Bureau delineation, July 2023).
Source: 2024 Gazetteer and 2020 place-by-county files, U.S. Census Bureau · Census reference files
How many people live in Big Rock Township, and is it growing?
The Census Bureau estimates that 1,739 people lived in Big Rock Township on July 1, 2025, down 2.2% since 2020, a steeper fall than Illinois's (−0.8%). The 2020 Census counted 1,768 residents. The 2020-2024 American Community Survey, a five-year sample, puts the population at 2,110 (±578).
| Measure | Big Rock Township | Kane County | Change since 2015-2019 |
|---|---|---|---|
| Total population | 2,110±578 | 517,255 | no clear change |
| Households | 814±307 | 184,706 | no clear change |
| Average household size | 2.59±0.44 | 2.77 | no clear change |
| Housing units | 843±303 | 190,921 | no clear change |
Big Rock Township's population since 2000
From 1,938 in 2000 to 1,739 in 2025: down 10.3%. The 2000, 2010 and 2020 figures are census counts, each for Big Rock Township as it was drawn that year: a place that annexed land, or a community that has since incorporated, covered a different area then. The 2005 figure is the Census Bureau's intercensal estimate, revised to fit the 2000 and 2010 counts and drawn on 2010 boundaries; 2015 and 2025 are July 1 estimates made from the census before them.
Source: The 2000, 2010 and 2020 Census counts and the Census Bureau's population estimates (intercensal 2000-2010, Vintage 2020, Vintage 2025) · Census population estimates
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); Census PEP Vintage 2025 (SUB-EST2025, CO-EST2025); 2020 Census P.L. 94-171 · Check it at data.census.gov
Who lives in Big Rock Township?
The median resident of Big Rock Township is 49.3 years old; 23.1% are under 18 and 14.4% are 65 or older. The largest group is non-Hispanic white residents at 76.9%, then non-Hispanic residents of two or more races at 13.5%.
| Measure | Big Rock Township | Kane County | Change since 2015-2019 |
|---|---|---|---|
| Median age | 49.3±11.5 | 38.8 | no clear change |
| Under 18 years | 23.1%±10.0 pts | 23.9% | – |
| 65 years and over | 14.4%±6.7 pts | 15.5% | – |
| Male | 49.1%±3.3 pts | 50.1% | – |
| Hispanic or Latino (any race) | 8.9%±5.8 pts | 33.4% | – |
| White alone, not Hispanic | 76.9%±12.1 pts | 54.0% | −18.9 pts |
| Black or African American alone, not Hispanic | 0.1%±0.2 pts | 4.7% | – |
| Asian alone, not Hispanic | 0.6%±0.4 pts | 4.0% | – |
| American Indian and Alaska Native alone, not Hispanic | 0.0%±1.8 pts | 0.1% | – |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.0%±1.8 pts | 0.0% | – |
| Two or more races, not Hispanic | 13.5%±13.8 pts | 3.4% | – |
| Some other race alone, not Hispanic | 0.0%±1.8 pts | 0.4% | – |
| Born outside the United States | 2.6%±1.9 pts | 17.2% | – |
| Speak a language other than English at home (age 5+) | 6.4%±5.4 pts | 31.8% | – |
| Civilian veterans (age 18+) | 2.1%±1.9 pts | 4.3% | – |
| With a disability | 4.2%±2.1 pts | 9.7% | – |
| No health insurance coverage | 1.0%±1.1 pts | 7.8% | – |
| High school graduate or higher (age 25+) | 98.0%±1.9 pts | 87.4% | – |
| Bachelor's degree or higher (age 25+) | 25.6%±13.4 pts | 38.1% | no clear change |
| Graduate or professional degree (age 25+) | 8.7%±5.6 pts | 13.6% | – |
| Lived in the same house a year earlier | 98.9%±1.0 pts | 90.1% | – |
| Moved from another state in the past year | 0.6%±0.9 pts | 0.9% | – |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profiles DP02, DP05) · Check it at data.census.gov
What do households in Big Rock Township earn?
Half of Big Rock Township's 814 households earn less than $158,250 a year (±$51,214), against $103,163 in Kane County and $83,390 in Illinois. In 2015-2019 it was $116,618 in 2024 dollars; the margins of error cannot tell the two periods apart.
| Measure | Big Rock Township | Kane County | Change since 2015-2019 |
|---|---|---|---|
| Median household income | $158,250±$51,214 | $103,163 | no clear change |
| Mean household income | $140,688±$15,700 | $131,975 | – |
| Per capita income | $53,494±$11,012 | $47,482 | no clear change |
| People below the poverty line | 10.7%±10.2 pts | 7.9% | – |
| Children under 18 below the poverty line | 33.0%±27.4 pts | 11.1% | – |
| Households receiving SNAP | 1.1%±1.1 pts | 11.0% | – |
| Households with a computer | 98.9%±1.1 pts | 97.1% | – |
| Households with a broadband subscription | 98.0%±1.7 pts | 93.3% | – |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov
What does housing cost in Big Rock Township?
Owners occupy 93.2% of Big Rock Township's occupied homes and renters 6.8%. The median owner-occupied home is valued at $336,400 by its owner (±$23,079). The median renter pays $1,653 a month including utilities.
| Measure | Big Rock Township | Kane County | Change since 2015-2019 |
|---|---|---|---|
| Median home value (owner-occupied) | $336,400±$23,079 | $327,000 | +$45,587 |
| Median gross rent | $1,653±$175 | $1,453 | no clear change |
| Renters paying 35% or more of income on rent | 0.0%±45.1 pts | 40.3% | – |
| Median monthly owner costs, with a mortgage | $2,555±$480 | $2,256 | – |
| Owner-occupied homes | 93.2%±5.9 pts | 76.0% | no clear change |
| Renter-occupied homes | 6.8%±5.9 pts | 24.0% | – |
| Housing units | 843±303 | 190,921 | no clear change |
| Homeowner vacancy rate | 1.8%±2.8 pts | 0.7% | – |
| Rental vacancy rate | 0.0%±43.0 pts | 3.1% | – |
| Single-family detached homes | 98.2%±2.5 pts | 69.1% | – |
| Mobile homes | 0.0%±4.3 pts | 0.8% | – |
| Built 2020 or later | 0.0%±4.3 pts | 1.4% | – |
| Built 2010 to 2019 | 0.5%±0.7 pts | 7.0% | – |
| Built 1939 or earlier | 44.6%±26.5 pts | 12.7% | – |
| Households with no vehicle | 0.7%±0.8 pts | 4.7% | – |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP04) · Check it at data.census.gov
How do people in Big Rock Township work and get to work?
65.7% of Big Rock Township's workers drive alone and 31.5% work from home. The average trip to work takes 18.6 minutes.
| Measure | Big Rock Township | Kane County | Change since 2015-2019 |
|---|---|---|---|
| In the labor force (age 16+) | 74.0%±12.9 pts | 69.5% | – |
| Unemployment rate | 1.8%±1.5 pts | 4.8% | – |
| Drove alone to work | 65.7%±11.1 pts | 70.7% | – |
| Carpooled | 1.5%±1.5 pts | 8.9% | – |
| Public transportation | 0.5%±0.9 pts | 1.6% | – |
| Walked | 0.3%±0.4 pts | 1.2% | – |
| Worked from home | 31.5%±12.7 pts | 15.9% | – |
| Mean travel time to work | 18.6 min±8.9 | 27.8 min | no clear change |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov
What census tracts are in Big Rock Township?
No census tract lies mostly in Big Rock Township; 1 tract reaches into it (2020 census blocks).
| Tract | Residents, 2020-2024 | Median household income |
|---|---|---|
| Tract 8524.03Kane County | 5,226 | $131,731 |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); 2020 block assignment files (tract share = share of the tract's census blocks in Big Rock Township) · Census block assignment files
How does Big Rock Township compare with other places in Illinois?
By the Census Bureau's July 2025 estimates, Big Rock Township is the 5,403rd-most populous of the 16,079 U.S. towns and townships that have one and the 478th-most populous of 1,407 in Illinois.
Big Rock Township ranks 44th of 1,380 places in Illinois with 1,000 or more residents and a reliable estimate, by median household income.
| Measure | Rank | Of |
|---|---|---|
| Population, July 2025 estimate | 478th | 1,407 |
| Growth 2020-2025 (PEP) | 739th | 1,347 |
| Residents per square mile | 1,165th | 1,383 |
| Median household income | 44th | 1,380 |
| Per capita income | 191st | 1,383 |
| Median home value | 181st | 1,379 |
| Median gross rent | 139th | 1,280 |
| Bachelor's degree or higher | 624th | 1,369 |
| Median age | 107th | 1,383 |
| Owner-occupied share | 108th | 1,382 |
| Work from home | 23rd | 1,015 |
| Travel time to work | 1,219th | 1,382 |
Big Rock Township's figures with every place in Illinois (CSV)
Every place in Illinois, sortable · Compare Big Rock Township with other places
Source: PlainCities ranks computed from the American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) and PEP Vintage 2025 · How ranks are computed
How reliable are the figures for Big Rock Township?
26 of the 57 figures for Big Rock Township on this page carry a coefficient of variation over 40% and are marked with a ring: they come from a small sample, so read them as rough.
The American Community Survey samples about one household in eight over five years, so every figure is an estimate with a 90% margin of error (shown under each value). A ring marks an estimate whose coefficient of variation is over 40%. A change is called only when the gap between the two periods is larger than their combined 90% margin (the square root of the sum of the two squared margins), the Census Bureau's test. How to read a margin of error.
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026): margins of error as published · ACS technical documentation
How these figures are made: methodology and release checks · reading a margin of error · every state · corrections
Not on this page: crime, weather and schools for Big Rock Township are other agencies' records. Crime: the FBI's Crime Data Explorer · climate: NOAA's U.S. Climate Normals · schools: the National Center for Education Statistics' school search.