618
Area code
IL
United States geographic area code, in service since 1947-01-01. Part of the 618/730 overlay complex — ten-digit dialing required.
Statusin service
Introduced1947-01-01
JurisdictionIL, US
Local dialing10D
Time zoneCentral
Last verified2026-09-17
Utilization 101% of assignable prefixes assigned
As of 09/17/2026
0%800 of ~792 assignable NXX values (200–999 excl. N11)100%
Prefix-level assignment does not equal number-level exhaustion; thousands-block pooling extends capacity. First assignment on record 2001-01-04, most recent 2025-06-18.
Area codes serve rate-center geographies, not municipal boundaries. “IL” identifies the jurisdiction, not an exact city footprint.
Top assignees
Ranked by assigned prefixes · initial assignee ≠ current carrier| Rank | Assignee | Prefixes | Share |
|---|---|---|---|
| 01 | FRONTIER NORTH, INC. - IL | 126 | 15.8% |
| 02 | ILLINOIS BELL TEL CO | 111 | 13.9% |
| 03 | NEW CINGULAR WIRELESS PCS, LLC - IL | 95 | 11.9% |
| 04 | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL | 62 | 7.8% |
| 05 | LEVEL 3 COMMUNICATIONS, LLC - IL | 46 | 5.8% |
| 06 | T-MOBILE USA, INC. | 40 | 5% |
| 07 | CITIZENS TELECOM CO ILLINOIS-FRONTIER CITIZENS -IL | 38 | 4.8% |
| 08 | ONVOY, LLC | 27 | 3.4% |
| 09 | BANDWIDTH.COM CLEC, LLC - IL | 21 | 2.6% |
| 10 | PAETEC ITEL, LLC | 14 | 1.8% |
Important: these are initial assignees from NANPA CO-code records — the carrier a prefix was originally assigned to. Because of number portability, the current serving carrier of any individual number may differ.
Change history
Recorded events for this NPA- 2022-06-15 NPA 730 to Overlay NPA 618 (Illinois)
- 1947-01-01Area code 618 entered service.
Planning letters & orders
Primary documents| Date | Document | Subject |
|---|---|---|
| 2022-06-15 | PL-595 ↗ | NPA 730 to Overlay NPA 618 (Illinois) |
| 2021-01-08 | PL-556 ↗ | Transition to 10-digit dialing (for 988 as 3-digit access to National Suicide Prevention Lifeline) – supersedes PL-544 |
| 2020-08-17 | PL-544 ↗ | Transition to 10-digit dialing (for 988 as 3-digit access to National Suicide Prevention Hotline |