Township · Illinois
Cortland Township, Illinois
Cortland Township, township, in DeKalb County, Illinois. Cortland Township had 11,644 residents on July 1, 2025 by the Census Bureau's estimate, up 4.0% since 2020; the 2020 Census counted 11,244 and the ACS 2020-2024 5-year estimates put it at 11,312 (±32). GEOID 1703716483.
Residents, July 2025 estimate
11,644
Census Bureau estimate (no margin published)
2020 Census count: 11,244 · ACS 2020-2024: 11,312 ±32
Median household income
$99,292
±$10,637 (90% margin)
Illinois: $83,390
Median home value
$263,500
±$11,457 (90% margin)
Illinois: $263,300
Median gross rent
$1,444
±$153 (90% margin)
Illinois: $1,274
Where is Cortland Township and what county is it in?
Cortland Township is a township in DeKalb County, Illinois. It covers 35.0 square miles of land, 321 residents per square mile in 2020.
One place lies inside Cortland Township: Cortland (town, 4,398 in 2020). Part of DeKalb (city), Sycamore (city) and Maple Park (village) also lie in it.
Cortland 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 Cortland Township, and is it growing?
The Census Bureau estimates that 11,644 people lived in Cortland Township on July 1, 2025, up 4.0% since 2020, while Illinois shrank 0.8%. The 2020 Census counted 11,244 residents. The 2020-2024 American Community Survey, a five-year sample, puts the population at 11,312 (±32).
| Measure | Cortland Township | DeKalb County | Change since 2015-2019 |
|---|---|---|---|
| Total population | 11,312±32 | 100,703 | +87 |
| Households | 4,106±190 | 39,550 | no clear change |
| Average household size | 2.75±0.13 | 2.42 | no clear change |
| Housing units | 4,233±211 | 41,678 | no clear change |
Cortland Township's population since 2000
From 6,986 in 2000 to 11,644 in 2025: up 66.7%. The 2000, 2010 and 2020 figures are census counts, each for Cortland 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 Cortland Township?
The median resident of Cortland Township is 35.1 years old; 25.7% are under 18 and 11.9% are 65 or older. The largest group is non-Hispanic white residents at 79.6%, then Hispanic or Latino residents (of any race) at 10.6%. 3.8% of residents were born outside the United States.
| Measure | Cortland Township | DeKalb County | Change since 2015-2019 |
|---|---|---|---|
| Median age | 35.1±2.4 | 32.7 | no clear change |
| Under 18 years | 25.7%±2.5 pts | 21.6% | – |
| 65 years and over | 11.9%±1.9 pts | 13.9% | – |
| Male | 50.6%±2.7 pts | 49.7% | – |
| Hispanic or Latino (any race) | 10.6%±2.5 pts | 14.5% | no clear change |
| White alone, not Hispanic | 79.6%±3.5 pts | 71.0% | no clear change |
| Black or African American alone, not Hispanic | 4.7%±2.2 pts | 6.8% | no clear change |
| Asian alone, not Hispanic | 0.6%±0.5 pts | 2.2% | – |
| American Indian and Alaska Native alone, not Hispanic | 0.0%±0.3 pts | 0.2% | – |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.0%±0.3 pts | 0.0% | – |
| Two or more races, not Hispanic | 4.5%±2.3 pts | 4.8% | – |
| Some other race alone, not Hispanic | 0.0%±0.3 pts | 0.5% | – |
| Born outside the United States | 3.8%±1.5 pts | 6.4% | no clear change |
| Speak a language other than English at home (age 5+) | 8.0%±2.3 pts | 12.0% | – |
| Civilian veterans (age 18+) | 3.5%±1.0 pts | 5.2% | – |
| With a disability | 10.5%±2.5 pts | 11.1% | – |
| No health insurance coverage | 3.9%±1.7 pts | 5.1% | no clear change |
| High school graduate or higher (age 25+) | 96.5%±1.3 pts | 92.2% | – |
| Bachelor's degree or higher (age 25+) | 40.9%±4.0 pts | 33.0% | no clear change |
| Graduate or professional degree (age 25+) | 19.2%±3.3 pts | 13.3% | – |
| Lived in the same house a year earlier | 84.1%±5.4 pts | 82.8% | – |
| Moved from another state in the past year | 2.8%±2.4 pts | 1.9% | – |
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 Cortland Township earn?
Half of Cortland Township's 4,106 households earn less than $99,292 a year (±$10,637), against $70,724 in DeKalb County and $83,390 in Illinois. In 2015-2019 it was $95,669 in 2024 dollars; the margins of error cannot tell the two periods apart. 6.0% of residents live below the poverty line.
| Measure | Cortland Township | DeKalb County | Change since 2015-2019 |
|---|---|---|---|
| Median household income | $99,292±$10,637 | $70,724 | no clear change |
| Mean household income | $113,752±$7,014 | $90,834 | – |
| Per capita income | $41,197±$2,827 | $36,298 | no clear change |
| People below the poverty line | 6.0%±2.9 pts | 14.8% | no clear change |
| Children under 18 below the poverty line | 9.9%±6.8 pts | 17.3% | – |
| Households receiving SNAP | 7.8%±3.1 pts | 14.7% | – |
| Households with a computer | 97.5%±1.4 pts | 96.4% | – |
| Households with a broadband subscription | 95.2%±2.2 pts | 92.7% | – |
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 Cortland Township?
Owners occupy 83.9% of Cortland Township's occupied homes and renters 16.1%. The median owner-occupied home is valued at $263,500 by its owner (±$11,457). The median renter pays $1,444 a month including utilities, and 43.6% of renters pay 35% or more of their income on rent.
| Measure | Cortland Township | DeKalb County | Change since 2015-2019 |
|---|---|---|---|
| Median home value (owner-occupied) | $263,500±$11,457 | $243,600 | +$49,482 |
| Median gross rent | $1,444±$153 | $1,049 | no clear change |
| Renters paying 35% or more of income on rent | 43.6%±15.4 pts | 46.3% | no clear change |
| Median monthly owner costs, with a mortgage | $1,991±$105 | $1,866 | – |
| Owner-occupied homes | 83.9%±3.8 pts | 61.4% | +11.8 pts |
| Renter-occupied homes | 16.1%±3.8 pts | 38.6% | – |
| Housing units | 4,233±211 | 41,678 | no clear change |
| Homeowner vacancy rate | 0.0%±1.1 pts | 0.2% | – |
| Rental vacancy rate | 0.0%±5.5 pts | 2.6% | – |
| Single-family detached homes | 71.6%±4.6 pts | 58.2% | – |
| Mobile homes | 1.3%±1.1 pts | 2.1% | – |
| Built 2020 or later | 1.1%±0.7 pts | 0.5% | – |
| Built 2010 to 2019 | 4.2%±1.7 pts | 4.0% | – |
| Built 1939 or earlier | 3.9%±1.9 pts | 16.0% | – |
| Households with no vehicle | 3.1%±1.6 pts | 6.4% | – |
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 Cortland Township work and get to work?
80.4% of Cortland Township's workers drive alone and 9.8% work from home. The average trip to work takes 26.3 minutes. The unemployment rate in 2020-2024 averaged 5.1%.
| Measure | Cortland Township | DeKalb County | Change since 2015-2019 |
|---|---|---|---|
| In the labor force (age 16+) | 71.9%±3.6 pts | 68.4% | – |
| Unemployment rate | 5.1%±2.4 pts | 6.8% | no clear change |
| Drove alone to work | 80.4%±5.2 pts | 74.8% | – |
| Carpooled | 6.9%±3.5 pts | 9.6% | – |
| Public transportation | 1.6%±1.4 pts | 0.8% | – |
| Walked | 0.4%±0.4 pts | 4.2% | – |
| Worked from home | 9.8%±2.6 pts | 9.3% | +6.4 pts |
| Mean travel time to work | 26.3 min±2.3 | 26.7 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 Cortland Township?
2 census tracts lie mostly in Cortland Township, and 5 more reach into it (2020 census blocks). Their median household incomes run from $87,917 (Tract 7) to $100,147 (Tract 16).
| Tract | Residents, 2020-2024 | Median household income |
|---|---|---|
| Tract 16DeKalb County | 4,521 | $100,147 |
| Tract 7DeKalb County | 3,870 | $87,917 |
| Tract 8DeKalb County | 6,318 | $51,782 |
| Tract 6DeKalb County | 5,963 | $73,450 |
| Tract 4.01DeKalb County | 4,491 | $101,287 |
| Tract 5DeKalb County | 3,884 | $67,250 |
| Tract 15DeKalb County | 4,042 | $57,122 |
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 Cortland Township) · Census block assignment files
How does Cortland Township compare with other places in Illinois?
By the Census Bureau's July 2025 estimates, Cortland Township is the 1,071st-most populous of the 16,079 U.S. towns and townships that have one and the 137th-most populous of 1,407 in Illinois.
Cortland Township ranks 353rd 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 | 137th | 1,407 |
| Growth 2020-2025 (PEP) | 64th | 1,347 |
| Residents per square mile | 837th | 1,383 |
| Median household income | 353rd | 1,380 |
| Per capita income | 558th | 1,383 |
| Median home value | 337th | 1,379 |
| Median gross rent | 227th | 1,280 |
| Poverty rate | 890th | 1,119 |
| Bachelor's degree or higher | 251st | 1,369 |
| Median age | 1,259th | 1,383 |
| Owner-occupied share | 403rd | 1,382 |
| Work from home | 606th | 1,015 |
| Travel time to work | 617th | 1,382 |
Cortland Township's figures with every place in Illinois (CSV)
Every place in Illinois, sortable · Compare Cortland 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 Cortland Township?
11 of the 57 figures for Cortland 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 Cortland 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.