North American Numbers Source-cited · ownership disclosed
Area code
861
In service
United States · since 2023

West-Central Illinois (overlay of 309)

Area code 861 is an all-services distributed overlay of area code 309, activated February 24, 2023, to relieve number exhaustion in west-central Illinois. It shares 309's exact geography - it does NOT overlay 217.

The essentials Numbering data · NumberResearch · as of 2026-09-18
Place
West-Central Illinois (overlay of 309)
Type
geographic
Status
in service
In service since
2023
Projected exhaust
2102 Q4

Status, dates and counts are read from NumberResearch (NANPA / CNAC / FCC records). Assignment records show initial assignees, not the carrier serving a number today.

A · Where it is

Where 861 is

West-central Illinois - identical footprint to 309 (Peoria, Bloomington-Normal, Illinois Quad Cities, Galesburg).

Communities served wholly or partly by 861:

PeoriaBloomingtonNormalMolineGalesburg

Matches 309's 200+ communities; new numbers are rare since 861 is distributed only after 309 exhausts.

B · Relationships

How it relates to other codes

The codes 861 was split from, spawned, or shares its area with. A split divides the map and changes some numbers; an overlay shares the same ground and changes none — what's the difference?

Overlay · 2023 309 West-Central Illinois (Peoria) 861 is the overlay code on 309's geography; new 861 assignments occur only after 309 codes exhaust.
What's changing. Active overlay of 309 (all-services distributed overlay) since Feb 24, 2023.
C · History

How 861 got here

2021-11-29
Illinois Commerce Commission announced area code 861 as relief for 309.
Source: Illinois.gov press release / Wikipedia
2023-02-24
861 became operational as the all-services distributed overlay of 309.
Source: Illinois.gov press release / Wikipedia
D · Capacity

How full it is

Prefixes assigned
20
Prefixes available
780
Thousands-blocks assigned
8

Prefix-assignment counts describe allocation to carriers, not how many individual numbers are in use. Full technical records: NumberResearch ↗.

Compare 861 with another code →
Sources
Wikipedia ↗
Area codes 309 and 861
Illinois.gov ↗
New 861 Area Code is Coming to the Illinois 309 Area Code Region
NumberResearch.org ↗
Live status, dates, assignment counts and exhaust forecast — data as of 2026-09-18 (CC BY 4.0).

Place, relationships and history above are compiled by North American Numbers from the sources listed and last checked 2026-09-18. A check date is not an expert review — see how this is made. Flag an error.