Census tract · Cook County
Census Tract 8121, Cook County, Illinois
Census Tract 8121, GEOID 17031812100, in Cook County, Illinois, entirely within Oak Park. 4,614 residents in the ACS 2020-2024 5-year estimates (±589); the 2020 Census counted 4,763.
Residents, 2020-2024
4,614
±589 (90% margin)
2020 Census count: 4,763
Median household income
$141,111
±$25,076 (90% margin)
Cook County: $83,498
Median home value
$446,200
±$19,437 (90% margin)
Cook County: $324,500
Median gross rent
$1,199
±$247 (90% margin)
Cook County: $1,435
Where is Census Tract 8121?
Census Tract 8121 is one of 1,332 census tracts in Cook County, Illinois. It covers 0.40 square miles of land, 11,848 residents per square mile in 2020. Its GEOID, 17031812100, names it uniquely (how tract numbers and GEOIDs work).
| Place | Share of the tract |
|---|---|
| Oak Park | 100% |
6 census tracts border Census Tract 8121: Tract 2504 ($47,723), Tract 2506, Tract 2513 ($43,138), Tract 8122 ($214,667), Tract 8124 ($238,472) and Tract 8125 ($66,757). The figure in brackets is each tract's median household income.
Whether a tract counts as low- or moderate-income for bank lending (the Community Reinvestment Act) is set by the FFIEC against its metro area's family income: look it up in the FFIEC census geocoder.
Source: 2024 Gazetteer and 2020 block assignment files, U.S. Census Bureau · Census reference files
How many people live in Census Tract 8121?
The 2020-2024 American Community Survey puts Census Tract 8121's population at 4,614 (±589) in 1,644 households; the 2020 Census counted 4,763 residents and 1,783 housing units.
| Measure | Tract 8121 | Oak Park |
|---|---|---|
| Total population | 4,614±589 | 53,292 |
| Households | 1,644±160 | 23,387 |
| Average household size | 2.81±0.21 | 2.26 |
| Housing units | 1,690±150 | 24,872 |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); 2020 Census P.L. 94-171 · Check it at data.census.gov
Who lives in Census Tract 8121?
The median resident of Census Tract 8121 is 40.4 years old; 30.5% are under 18 and 13.7% are 65 or older. The largest group is non-Hispanic white residents at 53.7%, then non-Hispanic Black residents at 29.7%. 3.4% of residents were born outside the United States.
| Measure | Tract 8121 | Oak Park |
|---|---|---|
| Median age | 40.4±2.7 | 40.3 |
| Under 18 years | 30.5%±4.5 pts | 23.9% |
| 65 years and over | 13.7%±2.9 pts | 17.7% |
| Hispanic or Latino (any race) | 11.3%±5.7 pts | 9.3% |
| White alone, not Hispanic | 53.7%±9.0 pts | 61.5% |
| Black or African American alone, not Hispanic | 29.7%±8.3 pts | 17.8% |
| Asian alone, not Hispanic | 1.1%±0.8 pts | 5.1% |
| American Indian and Alaska Native alone, not Hispanic | 0.0%±0.8 pts | 0.0% |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.0%±0.8 pts | 0.0% |
| Two or more races, not Hispanic | 4.2%±2.6 pts | 5.9% |
| Some other race alone, not Hispanic | 0.0%±0.8 pts | 0.3% |
| Born outside the United States | 3.4%±1.4 pts | 9.2% |
| Speak a language other than English at home (age 5+) | 7.9%±3.9 pts | 14.5% |
| Civilian veterans (age 18+) | 3.8%±2.5 pts | 3.4% |
| With a disability | 11.4%±3.7 pts | 9.7% |
| No health insurance coverage | 1.6%±1.0 pts | 3.1% |
| High school graduate or higher (age 25+) | 95.7%±3.2 pts | 97.6% |
| Bachelor's degree or higher (age 25+) | 64.3%±9.4 pts | 72.5% |
| Graduate or professional degree (age 25+) | 37.8%±7.8 pts | 38.7% |
| Lived in the same house a year earlier | 94.1%±4.1 pts | 86.9% |
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 Census Tract 8121 earn?
Half of the 1,644 households in Census Tract 8121 earn less than $141,111 a year (±$25,076), against $83,498 across Cook County: 151st highest of the county's 1,258 tracts with a reliable estimate.
| Measure | Tract 8121 | Oak Park |
|---|---|---|
| Median household income | $141,111±$25,076 | $110,820 |
| Mean household income | $186,037±$23,632 | $161,118 |
| Per capita income | $66,682±$9,581 | $71,362 |
| People below the poverty line | 3.7%±2.5 pts | 7.4% |
| Children under 18 below the poverty line | 1.5%±2.3 pts | 8.6% |
| Households receiving SNAP | 8.8%±4.7 pts | 8.4% |
| Households with a computer | 100.0%±2.3 pts | 97.7% |
| Households with a broadband subscription | 99.6%±0.7 pts | 94.1% |
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 Census Tract 8121?
Owners occupy 88.9% of Census Tract 8121's occupied homes and renters 11.1%. The median owner-occupied home is valued at $446,200 by its owner (±$19,437). The median renter pays $1,199 a month including utilities, and 67.6% of renters pay 35% or more of their income on rent.
| Measure | Tract 8121 | Oak Park |
|---|---|---|
| Median home value (owner-occupied) | $446,200±$19,437 | $465,500 |
| Median gross rent | $1,199±$247 | $1,593 |
| Renters paying 35% or more of income on rent | 67.6%±25.8 pts | 36.0% |
| Median monthly owner costs, with a mortgage | $2,965±$266 | $3,202 |
| Owner-occupied homes | 88.9%±4.8 pts | 60.0% |
| Renter-occupied homes | 11.1%±4.8 pts | 40.0% |
| Housing units | 1,690±150 | 24,872 |
| Single-family detached homes | 86.5%±4.9 pts | 39.7% |
| Mobile homes | 0.0%±2.2 pts | 0.0% |
| Built 2020 or later | 0.0%±2.2 pts | 0.3% |
| Built 2010 to 2019 | 0.5%±0.8 pts | 3.9% |
| Built 1939 or earlier | 86.6%±4.8 pts | 59.3% |
| Households with no vehicle | 8.0%±4.8 pts | 11.7% |
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 Census Tract 8121 get to work?
41.4% of Census Tract 8121's workers drive alone and 42.2% work from home. The average trip to work takes 30.5 minutes.
| Measure | Tract 8121 | Oak Park |
|---|---|---|
| In the labor force (age 16+) | 77.8%±4.8 pts | 70.2% |
| Unemployment rate | 6.7%±4.8 pts | 5.6% |
| Drove alone to work | 41.4%±9.4 pts | 45.0% |
| Carpooled | 4.7%±5.9 pts | 4.3% |
| Public transportation | 7.0%±3.5 pts | 13.1% |
| Walked | 2.8%±2.6 pts | 4.3% |
| Worked from home | 42.2%±10.1 pts | 31.0% |
| Mean travel time to work | 30.5 min±2.8 | 31.6 min |
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
How does Census Tract 8121 compare with the other tracts in Cook County?
Among Cook County's tracts with a reliable estimate, Census Tract 8121 ranks as shown below (1 = highest).
| Measure | In Cook County | In Oak Park |
|---|---|---|
| Population | 428th of 1,328 | 3rd of 14 |
| Residents per square mile | 577th of 1,331 | 8th of 14 |
| Median household income | 151st of 1,258 | 6th of 14 |
| Per capita income | 264th of 1,325 | 7th of 14 |
| Median home value | 290th of 1,279 | 8th of 14 |
| Median gross rent | 907th of 1,254 | 11th of 12 |
| Bachelor's degree or higher | 283rd of 1,264 | 13th of 14 |
| Median age | 510th of 1,327 | 8th of 14 |
| Owner-occupied share | 152nd of 1,300 | 3rd of 14 |
The tracts next to it on Cook County's income ladder
| Tract | Rank | Median household income |
|---|---|---|
| Tract 2429 | 148th | $141,645±$28,731 · within the margin of this tract |
| Tract 505 | 149th | $141,563±$19,907 · within the margin of this tract |
| Tract 1202 | 150th | $141,458±$39,506 · within the margin of this tract |
| Tract 8121 | 151st | $141,111±$25,076 |
| Tract 8419 | 152nd | $141,017±$20,013 · within the margin of this tract |
| Tract 8097 | 153rd | $140,714±$33,562 · within the margin of this tract |
| Tract 8132 | 154th | $140,346±$25,701 · within the margin of this tract |
"Within the margin": the two incomes differ by less than their combined 90% margins, so the survey cannot say which is higher and the ranks between them are not firm.
Source: PlainCities ranks computed from the American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) · How ranks are computed
How reliable are the figures for Census Tract 8121?
2 of the 18 figures for Census Tract 8121 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.
A census tract's figures rest on a few hundred sampled households over five years, so its margins are wider than a city's. Two tracts differ only when the gap between them is larger than their combined 90% margin (the square root of the sum of the two squared margins). 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 · Check it at data.census.gov
How these figures are made: methodology and release checks · reading a margin of error · every state · corrections