DeKalb County, Illinois
DeKalb County, Illinois, has 101,835 residents (July 2025 estimate). Its county seat is Sycamore. It uses Central Time and covers 631 sq mi (1,635 km²) of land.
- Resident population, July 2025
- 101,835
- Land area
- 631 sq mi (1,635 km²)
- County seat or government
- Sycamore
- Time zone
- Central TimeUTC-06:00 in January; UTC-05:00 in July
- Median household income
- $70,724 ± $2,546
- Median home value
- $243,600 ± $5,310
- Median rent, with utilities
- $1,049 ± $33
- Homes lived in by their owners
- 61.4% ± 1.3 points
- County type
- County
- Metro or micro area
- Chicago-Naperville-Elgin, IL-IN metro areaOutlying county
- Water area
- 3.31 sq mi (8.56 km²)
- State
- Illinois
- County code (FIPS)
- 17037
- Coordinates (central point)
- 41.894615, -88.768922
These coordinates mark a central point for the area, not a street address. Income, home value, rent and homes lived in by their owners: U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates, ± margin at 90% confidence; checked on October 13, 2026.
Time zones in DeKalb County
| Time zone | Local time and UTC offset | Next clock change |
|---|---|---|
| Central TimeAmerica/Chicago | UTC-06:00 in January; UTC-05:00 in July. Enable JavaScript for the live clock. | Enable JavaScript for upcoming changes. |
Near a time-zone line, check where you are with the time-zone finder. Your phone’s setting can differ.
ZIP Code areas, largest first
- 6011542,536 people
- 6014022,689 people
- 6017822,224 people
- 6106814,788 people
- 6015212,417 people
- 6054811,721 people
- 601357,274 people
- 601124,621 people
- 605524,285 people
- 601513,888 people
- 605183,289 people
- 605202,979 people
All 22
22 ZIP Code areas overlap DeKalb County. People counts are 2020–2024 estimates for each whole ZIP area. Mailing ZIPs can differ; check an address with USPS ZIP Code Lookup.
Official county information
We don’t have a website for this county yet. The US government’s local-office directory ↗ lists its offices. A geographic lookup cannot determine eligibility, tax liability or a court obligation.
Townships in DeKalb County, largest first
- DeKalb Township42,778 people
- Sycamore Township14,846 people
- Cortland Township11,312 people
- Sandwich Township7,529 people
- Genoa Township5,606 people
- Kingston Township3,464 people
- Squaw Grove Township2,716 people
- Franklin Township2,286 people
- Clinton Township2,149 people
- Somonauk Township1,827 people
- Malta Township1,741 people
- Shabbona Township1,082 people
All 19
- Afton Township938 people
- Mayfield Township851 people
- Pierce Township554 people
- South Grove Township352 people
- Milan Township286 people
- Paw Paw Township198 people
- Victor Township188 people
People counts are American Community Survey 2020–2024 5-year estimates. All townships in Illinois, by county
School districts in DeKalb County, largest first
- Community Unit School District 300120,443 people
- DeKalb Community Unit School District 42849,018 people
- Belvidere Consolidated Unit School District 10044,668 people
- Kaneland Community Unit School District 30226,458 people
- Sycamore Community Unit School District 42722,192 people
- Central Community Unit School District 30121,751 people
- Rochelle Township High School District 21217,138 people
- Sandwich Community Unit School District 43013,374 people
- Genoa-Kingston Community Unit School District 4249,221 people
- Hinckley-Big Rock Community Unit School District 4295,294 people
- Somonauk Community Unit School District 4324,784 people
- Indian Creek Community Unit District 4254,283 people
All 19
- Earlville Community Unit School District 92,791 people
- Hiawatha Community Unit School District 4262,603 people
- Leland Community Unit School District 12,042 people
- Paw Paw CUSD 2711,588 people
- Eswood Community Consolidated District 269849 people
- Creston Community Consolidated School District 161814 people
- Steward Elementary School District 220737 people
Districts with land in the county; a district can cross county lines. People counts are American Community Survey 2020–2024 5-year estimates. A district boundary doesn’t decide which school a student attends.
Cities, towns and communities, largest first
These areas overlap the mapped boundary; an overlap does not mean that every address belongs to both.
- DeKalb, Illinois (city)40,443 people
- Sycamore, Illinois (city)18,559 people
- Sandwich, Illinois (city)7,219 people
- Genoa, Illinois (city)5,492 people
- Cortland, Illinois (town)4,564 people
- Hinckley, Illinois (village)2,331 people
- Maple Park, Illinois (village)1,573 people
- Somonauk, Illinois (village)1,569 people
- Kirkland, Illinois (village)1,525 people
- Waterman, Illinois (village)1,448 people
- Kingston, Illinois (village)1,352 people
- Malta, Illinois (village)1,274 people
All 14
- Shabbona, Illinois (village)572 people
- Lee, Illinois (village)320 people
Bordering areas, nearest first
Distances are straight lines between map points.
- Kane County, Illinois18 mi east
- Kendall County, Illinois27 mi southeast
- Lee County, Illinois29 mi west
- Boone County, Illinois29 mi north
- Ogle County, Illinois30 mi west
- McHenry County, Illinois34 mi northeast
- Winnebago County, Illinois37 mi northwest
- LaSalle County, Illinois39 mi south
Before using this answer on a form
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