Census-designated place · Illinois
Knollwood, Illinois
Knollwood, census-designated place, in Lake County, Illinois. Knollwood had 2,121 residents in the 2020 Census, a full count; the ACS 2020-2024 5-year estimates put it at 1,864 (±578). GEOID 1740364.
Residents, 2020 Census
2,121
Census count or controlled total
ACS 2020-2024 estimate: 1,864 ±578
Median household income
$138,618
±$86,965 (90% margin)
Illinois: $83,390
Median home value
$393,000
±$44,821 (90% margin)
Illinois: $263,300
Median gross rent
$1,659
±$333 (90% margin)
Illinois: $1,274
Where is Knollwood and what county is it in?
Knollwood is a census-designated place: an unincorporated community the Census Bureau draws for counting, with no city government of its own, in Lake County, Illinois. It covers 0.6 square miles of land, 3,506 residents per square mile in 2020.
Knollwood is in the Chicago-Naperville-Elgin, IL-IN metropolitan statistical area, which takes in 13 counties (Census Bureau delineation, July 2023).
Knollwood lies mostly within Shields Township and reaches into Libertyville Township, towns or townships with their own local government (2020 census blocks).
Source: 2024 Gazetteer and 2020 place-by-county files, U.S. Census Bureau · Census reference files
How many people live in Knollwood, and is it growing?
The 2020 Census counted 2,121 residents in Knollwood, a full count rather than a sample. The 2020-2024 American Community Survey, a sample, estimates 1,864 (±578).
The Census Bureau publishes yearly population estimates for incorporated places only; Knollwood is a census-designated place, so its figures come from the ACS and the 2020 Census.
| Measure | Knollwood | Lake County | Change since 2015-2019 |
|---|---|---|---|
| Total population | 1,864 ±578 | 714,223 | no clear change |
| Households | 591 ±124 | 258,455 | no clear change |
| Average household size | 2.98 ±0.54 | 2.69 | no clear change |
| Housing units | 688 ±150 | 270,618 | no clear change |
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 Knollwood?
The median resident of Knollwood is 36.4 years old; 36.6% are under 18 and 19.3% are 65 or older. The largest group is non-Hispanic white residents at 73.2%, then Hispanic or Latino residents (of any race) at 18.8%.
| Measure | Knollwood | Lake County | Change since 2015-2019 |
|---|---|---|---|
| Median age | 36.4 ±10.2 | 39.1 | no clear change |
| Under 18 years | 36.6% ±9.5 pts | 23.3% | – |
| 65 years and over | 19.3% ±9.3 pts | 15.8% | – |
| Male | 48.6% ±5.4 pts | 50.3% | – |
| Hispanic or Latino (any race) | 18.8% ±9.1 pts | 24.9% | no clear change |
| White alone, not Hispanic | 73.2% ±12.7 pts | 56.2% | no clear change |
| Black or African American alone, not Hispanic | 6.2% ±8.9 pts | 6.3% | – |
| Asian alone, not Hispanic | 1.8% ±2.4 pts | 8.6% | – |
| American Indian and Alaska Native alone, not Hispanic | 0.0% ±2.0 pts | 0.1% | – |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.0% ±2.0 pts | 0.0% | – |
| Two or more races, not Hispanic | 0.0% ±2.0 pts | 3.3% | – |
| Some other race alone, not Hispanic | 0.0% ±2.0 pts | 0.6% | – |
| Born outside the United States | 9.7% ±7.5 pts | 19.8% | – |
| Speak a language other than English at home (age 5+) | 15.7% ±8.3 pts | 31.4% | – |
| Civilian veterans (age 18+) | 3.4% ±3.1 pts | 4.7% | – |
| With a disability | 10.4% ±5.5 pts | 9.8% | – |
| No health insurance coverage | 0.5% ±0.9 pts | 6.9% | – |
| High school graduate or higher (age 25+) | 96.6% ±3.3 pts | 90.6% | – |
| Bachelor's degree or higher (age 25+) | 43.2% ±9.4 pts | 47.7% | no clear change |
| Graduate or professional degree (age 25+) | 8.5% ±6.2 pts | 20.1% | – |
| Lived in the same house a year earlier | 96.6% ±3.3 pts | 88.4% | – |
| Moved from another state in the past year | 0.0% ±2.0 pts | 2.9% | – |
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 Knollwood earn?
Half of Knollwood's 591 households earn less than $138,618 a year (±$86,965), against $110,416 in Lake County and $83,390 in Illinois. In 2015-2019 it was $127,684 in 2024 dollars; the margins of error cannot tell the two periods apart.
| Measure | Knollwood | Lake County | Change since 2015-2019 |
|---|---|---|---|
| Median household income | $138,618 ±$86,965 | $110,416 | no clear change |
| Mean household income | $144,329 ±$29,740 | $155,726 | – |
| Per capita income | $46,813 ±$11,393 | $57,153 | no clear change |
| People below the poverty line | 7.8% ±10.5 pts | 8.3% | – |
| Children under 18 below the poverty line | 12.0% ±18.7 pts | 11.5% | – |
| Households receiving SNAP | 12.5% ±11.9 pts | 9.4% | – |
| Households with a computer | 97.6% ±3.7 pts | 97.2% | – |
| Households with a broadband subscription | 100.0% ±6.1 pts | 94.3% | – |
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 Knollwood?
Owners occupy 77.8% of Knollwood's occupied homes and renters 22.2%. The median owner-occupied home is valued at $393,000 by its owner (±$44,821). The median renter pays $1,659 a month including utilities, and 70.1% of renters pay 35% or more of their income on rent.
| Measure | Knollwood | Lake County | Change since 2015-2019 |
|---|---|---|---|
| Median home value (owner-occupied) | $393,000 ±$44,821 | $345,700 | no clear change |
| Median gross rent | $1,659 ±$333 | $1,477 | no clear change |
| Renters paying 35% or more of income on rent | 70.1% ±33.0 pts | 40.1% | – |
| Median monthly owner costs, with a mortgage | $2,437 ±$509 | $2,503 | – |
| Owner-occupied homes | 77.8% ±14.3 pts | 74.8% | +18.0 pts |
| Renter-occupied homes | 22.2% ±14.3 pts | 25.2% | – |
| Housing units | 688 ±150 | 270,618 | no clear change |
| Homeowner vacancy rate | 0.0% ±7.8 pts | 0.9% | – |
| Rental vacancy rate | 0.0% ±24.5 pts | 3.7% | – |
| Single-family detached homes | 84.4% ±12.6 pts | 66.6% | – |
| Mobile homes | 1.2% ±2.2 pts | 1.6% | – |
| Built 2020 or later | 0.0% ±5.3 pts | 0.6% | – |
| Built 2010 to 2019 | 1.9% ±3.2 pts | 4.9% | – |
| Built 1939 or earlier | 0.0% ±5.3 pts | 8.4% | – |
| Households with no vehicle | 0.0% ±6.1 pts | 4.6% | – |
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 Knollwood work and get to work?
59.2% of Knollwood's workers drive alone and 34.8% work from home. The average trip to work takes 21.0 minutes.
| Measure | Knollwood | Lake County | Change since 2015-2019 |
|---|---|---|---|
| In the labor force (age 16+) | 48.2% ±8.4 pts | 68.2% | – |
| Unemployment rate | 0.0% ±6.8 pts | 5.2% | – |
| Drove alone to work | 59.2% ±17.0 pts | 65.7% | – |
| Carpooled | 2.1% ±2.9 pts | 8.5% | – |
| Public transportation | 0.0% ±5.9 pts | 2.7% | – |
| Walked | 0.0% ±5.9 pts | 2.1% | – |
| Worked from home | 34.8% ±17.4 pts | 19.5% | – |
| Mean travel time to work | 21.0 min ±3.9 | 28.5 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 Knollwood?
No census tract lies mostly in Knollwood; 2 tracts reach into it (2020 census blocks).
| Tract | Residents, 2020-2024 | Median household income |
|---|---|---|
| Tract 8632.02Lake County | 5,543 | $163,190 |
| Tract 8637.02Lake County | 4,127 | $93,542 |
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 Knollwood) · Census block assignment files
How does Knollwood compare with other places in Illinois?
Knollwood ranks 82nd of 1,380 places in Illinois with 1,000 or more residents and a reliable estimate, by median household income.
| Measure | Rank | Of |
|---|---|---|
| Population (ACS 2020-2024) | 987th | 1,383 |
| Residents per square mile | 127th | 1,383 |
| Median household income | 82nd | 1,380 |
| Per capita income | 343rd | 1,383 |
| Median home value | 100th | 1,379 |
| Median gross rent | 134th | 1,280 |
| Bachelor's degree or higher | 226th | 1,369 |
| Median age | 1,171st | 1,383 |
| Owner-occupied share | 689th | 1,382 |
| Work from home | 10th | 1,015 |
| Travel time to work | 1,067th | 1,382 |
Knollwood's figures with every place in Illinois (CSV)
Every place in Illinois, sortable · Compare Knollwood 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 Knollwood?
25 of the 57 figures for Knollwood 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 Knollwood 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.