815
Area code
IL
United States geographic area code, in service since 1947-01-01. Part of the 779/815 overlay complex — ten-digit dialing required.
Statusin service
Introduced1947-01-01
JurisdictionIL, US
Local dialing1+10D
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 2001-01-24, most recent 2025-05-16.
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 | ILLINOIS BELL TEL CO | 157 | 19.6% |
| 02 | FRONTIER NORTH, INC. - IL | 133 | 16.6% |
| 03 | LEVEL 3 COMMUNICATIONS, LLC - IL | 76 | 9.5% |
| 04 | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL | 50 | 6.3% |
| 05 | AERO NORTH COMMUNICATIONS, INC. - IL | 43 | 5.4% |
| 06 | NEW CINGULAR WIRELESS PCS, LLC - IL | 42 | 5.3% |
| 07 | T-MOBILE USA, INC. | 40 | 5% |
| 08 | UNITED STATES CELLULAR - IL | 23 | 2.9% |
| 09 | TELEPORT COMMUNICATIONS AMERICA, LLC - IL | 22 | 2.8% |
| 10 | METROPCS, INC. | 17 | 2.1% |
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- 2006-05-15 NPA 779 to Overlay NPA 815 (Illinois)
- 1947-01-01Area code 815 entered service.
Planning letters & orders
Primary documents| Date | Document | Subject |
|---|---|---|
| 2006-05-15 | PL-354 ↗ | NPA 779 to Overlay NPA 815 (Illinois) |