Created in 1957 from a division of the 815 numbering plan area (with roots in the 1956 reorganization of northern 217 territory), 309 serves west-central Illinois. It has been overlaid by area code 861 since February 2023.
The essentialsNumbering data · NumberResearch · as of 2026-09-18
Place
West-Central Illinois (Peoria)
Type
geographic
Status
in service
In service since
1957
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 309 is
West-central Illinois - the Peoria metro, Bloomington-Normal, the Illinois (western) side of the Quad Cities, and Galesburg.
Communities served wholly or partly by 309:
PeoriaBloomingtonNormalMolineGalesburg
Representative subset; the NPA spans 200+ communities.
B · Relationships
How it relates to other codes
The codes 309 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?
Split from · 1957815Northern Illinois (Rockford)309 was carved from the western half of the 815 NPA in 1957.
Split from · 1956217Central Illinois (Springfield)The Peoria/Bloomington-Normal territory feeding 309 was originally in 217 before the 1956 reorganization.
Overlay · 2023861West-Central Illinois (overlay of 309)All-services distributed overlay of 309, effective Feb 24, 2023.
What's changing. Overlaid by 861 (all-services distributed overlay) since Feb 24, 2023.
C · History
How 309 got here
1956
Northern 217 territory (Peoria, Bloomington-Normal) reorganized in preparation for a new NPA.
Source: Wikipedia - Area code 309
1957
815 NPA divided; western part assigned area code 309.
Source: Wikipedia - Area code 309
2021-10-24
Transitioned to mandatory 10-digit dialing due to nationwide 988 implementation.
Source: Wikipedia - Area code 309
2023-02-24
Area code 861 became operational as the all-services overlay of 309.
Source: Wikipedia - Area codes 309 and 861
D · Capacity
How full it is
Prefixes assigned
800
Prefixes available
0
Thousands-blocks assigned
3,303
Prefix-assignment counts describe allocation to carriers, not how many individual numbers are in use. Full technical records: NumberResearch ↗.
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.
North American Numbers