Area Code Overview
Area code 861 is a geographic telephone area code in Illinois that went into service on February 24, 2023. The geographic regions covered by this area code overlay has a population of approximately 888,642.
Overlay and Dialing Rules
- Area Code: 861
- State: Illinois
- Type: General Purpose Code
- In Service Date: February 24, 2023
- Overlay Complex: 309/861
- Local Dialing Plan: This area does require you to dial the area code when calling locally.
Estimated Number of Assigned Phone Numbers in Area Code 861
Estimated Service-Type Mix of Assigned Phone Numbers in Area Code 861
No usage distribution is available for this area code.
Estimated Share of Wireless Numbers Originally Assigned to Each Carrier in Area Code 861
Estimated assigned wireless phone numbers: 0
Numbers may later be ported to another carrier, but this chart reflects original number assignment, not current subscriber share.
No wireless provider distribution is available for this area code.
Estimated Share of Wireline and VoIP Numbers Originally Assigned to Each Carrier in Area Code 861
Estimated assigned wireline and VoIP phone numbers: 0
No wireline or VoIP provider distribution is available for this area code.
Other / Unclassified Assigned Numbering in Area Code 861
Estimated assigned other or unclassified phone numbers: 0
No other or unclassified provider distribution is available for this area code.
Cities and Towns in Area Code 861
These geographic regions are also served by area code 309.
How These Figures Were Built
These figures are estimates based on public phone-number assignment records. They are meant to show the likely mix of assigned phone numbers associated with area code 861, not live customer counts.
Some providers may have assigned phone numbers tied to this area code even if they do not actively market or sell service locally. These figures reflect public number-assignment records, not confirmed local service availability.
They also do not reflect number portability at the individual phone-number level, so some numbers may now be used on a different network or by a different provider than the original assignment records suggest.
Population data and locality matching provided by GeoNames.
Last refreshed: April 15, 2026 6:22 pm