Area code lookup
861 area code
- State
- IL
- Codes in state
- 17
- Overlays & neighbours
- 16
- Time zone
- Central Time
Quick answer
Area code 861 is a geographic area code assigned to Illinois under the North American Numbering Plan. Illinois observes Central Time, and the state also holds 16 other area codes: 217, 224, 309, 312, 331, 447, 464, 618, 630, 708, 730, 773, 779, 815, 847, 872.
Largest cities in Illinois
The largest places in Illinois. Each links to its full local profile: population, income, housing and sales tax.
| City | Population |
|---|---|
| Chicago city | 2,707,648 |
| Aurora city | 179,867 |
| Joliet city | 149,785 |
| Naperville city | 149,424 |
| Rockford city | 147,649 |
| Elgin city | 114,106 |
| Springfield city | 113,714 |
| Peoria city | 112,126 |
| Waukegan city | 88,919 |
| Champaign city | 88,822 |
| Cicero town | 83,223 |
| Bloomington city | 78,703 |
Related area codes
Codes that share or border the same calling area.
861 area code FAQ
The questions people ask about this code.
Where is area code 861?
861 is a geographic area code in Illinois.
What time is it in the 861 area code?
861 observes Central Time.
Is 861 a scam area code?
No — it is a normal geographic code, not a toll-free or premium-rate prefix. Caller ID can be spoofed on any code, so verify unexpected callers before sharing information.
Sources & transparency
- North American Numbering Plan Administrator (NANPA) area code assignments — area code to geography mapping and overlay relationships
- US Census Bureau, American Community Survey 2019-2023 5-year estimates — city, county and ZIP code geography
Last reviewed August 2026. Figures are published for reference and can change; verify with the source agency before filing or contracting. How we build and check this data.