Area Code 224
Illinois
Area code 224 serves Illinois, primarily Chicago, in the Central Time (CT) time zone. It is an overlay area code sharing territory with area code 847.
Overlay Area Code
This area code is part of an overlay region, meaning the same geographic area is served by multiple area codes. Overlay codes were introduced to meet growing demand for phone numbers without requiring existing customers to change their numbers.
This area code shares its geographic region with: area code 847 (Chicago).
In service since: 05-Jan-2002
Historical Timeline of Area Code 224
Area code 224 was put into service on January 5, 2002 as an overlay for area code 847 in northeastern Illinois. The overlay was necessitated by central office code exhaustion in the 847 NPA, which NANPA declared in January 2001 after a contested regulatory process involving the Illinois Commerce Commission, the Citizens Utility Board, and the Cook County State's Attorney. Source: NANPA Planning Letters
Key milestones:
- 1989: Area code 708 split from 312, serving Chicago suburbs (Wikipedia)
- 1996: Area code 847 created in a three-way split of 708, serving northern Chicago suburbs including Evanston, Waukegan, and Arlington Heights (Wikipedia)
- 1998: NANPA published Planning Letter PL-127 (June 12, 1998) establishing the 847/224 overlay. ICC adopted number pooling and all-services overlay as backup relief plan in Dockets 97-0192/97-0211 (NANPA PL-127)
- 1998: First trial of telephone number pooling in the United States launched in the 847 NPA (June 1998) to avert central office code exhaustion (Wikipedia)
- 1998: ICC Docket 98-0497 Final Order (December 16, 1998) established conservation measures, carrier reporting requirements, and a 30-day advance notice framework before first 224 NXX assignment (Illinois Commerce Commission)
- 2001: NANPA declared 847 NPA exhaustion (January 11-12, 2001) and filed formal notification with ICC on January 17, 2001. Citizens Utility Board and Cook County State's Attorney challenged the assertion, citing 29 unassignable NXX codes (ICC Docket 01-0066)
- 2001: ICC rejected NANPA's exhaust notice (February 2001) and directed NeuStar to reevaluate 847 exhaustion status. Prohibited issuing any 224 NXX codes until reevaluation was complete (ICC Staff Response)
- 2002: Area code 224 officially put into service (January 5, 2002) as an overlay of 847, requiring mandatory 10-digit dialing (Wikipedia)
- 2004: NANPA Planning Letter PL-277 established the mandatory dialing date for the 847/224 overlay complex (NANPA PL-277)
The 847/224 overlay represents one of the more contentious numbering relief proceedings in Illinois history. The ICC's rejection of NANPA's January 2001 exhaust notice, prompted by challenges from the Citizens Utility Board and Cook County State's Attorney, delayed 224 implementation until January 2002. The overlay ultimately required mandatory 10-digit dialing for all subscribers in the 847 numbering plan area.
Unique Facts About Area Code 224
From its earliest days, area code 224 has played a specific role in the region.
- Contested Number Exhaustion: The 847/224 overlay was the subject of a contested exhaustion proceeding. The ICC rejected NANPA's January 2001 exhaust notice and directed NeuStar to reevaluate before any 224 codes could be assigned. This regulatory conflict delayed the overlay's implementation by over a year. (ICC Docket 01-0066, February 2001)
- 29 Unassignable NXX Codes: Of the 800 NXX codes in the 847 NPA, 29 were designated as unassignable: 12 Oddball codes, 5 Test codes, 1 Special Use code, 1 Reserved code, and 10 Protected codes. Challengers cited this breakdown to argue that exhaustion had not truly occurred. (NANPA/ICC meeting minutes, January 2001)
- Cook County State's Attorney Challenge: The Cook County State's Attorney filed a motion challenging whether 847 was truly exhausted, requesting a stay of customer education for the 224 overlay pending NeuStar's demonstration of exhaustion. (ICC Docket 01-0066, January 22, 2001)
- FCC Waiver Expiration: An FCC waiver of the 10-digit dialing requirement under 47 C.F.R. §52.19(c)(3)(ii) was set to expire April 1, 2001, creating regulatory urgency during the contested exhaust period. (Illinois Commerce Commission)
- First US Number Pooling Trial: The 847 NPA was the site of the first trial of telephone number pooling in the United States in June 1998, a conservation measure intended to forestall the exhaustion that ultimately required the 224 overlay. (Wikipedia)
The contested nature of the 847 exhaustion proceeding and the detailed breakdown of unassignable codes make the 224 overlay a notable case study in telephone number resource management.
FCC Regulatory History
Area code 224 has undergone significant regulatory events spanning three Illinois Commerce Commission dockets and multiple NANPA planning letters over a six-year period from 1998 to 2004. The regulatory proceedings established the framework for number conservation, overlay implementation, and mandatory dialing in the 847/224 numbering plan area. Source: Illinois Commerce Commission
| Docket / Document | Date | Authority | Outcome |
|---|---|---|---|
| ICC Docket 97-0192 | May 11, 1998 | Illinois Commerce Commission | Adopted thousands-block number pooling and all-services overlay as backup relief plan for 847 NPA. Defined the 'irreversible act' triggering overlay as assignment of the first CO code from the 224 NPA. (ICC) |
| NANPA PL-127 | June 12, 1998 | NANPA | Published planning letter establishing the overlay of 847 with 224 (superseded by PL-NANP-109). (NANPA) |
| ICC Docket 98-0497 (Final Order) | December 16, 1998 | Illinois Commerce Commission | Directed carriers to report individual number utilization rates, mandated return of contaminated thousand-blocks, established 30-day advance notice requirement before first 224 NXX assignment. (ICC) |
| ICC Docket 98-0497 (Rehearing) | February 3, 1999 | Illinois Commerce Commission | Clarified that NANPA must give the Commission and interested parties at least 30 days advance notice before assigning the first 224 NXX code, including the effective date. (ICC) |
| ICC Docket 01-0066 (NANPA Notification) | January 17, 2001 | NANPA / ICC | NANPA formally notified ICC that 847 NPA was exhausted. Last 847 CO code request received January 3, 2001. First 224 NXX code scheduled for February 16, 2001. (ICC Docket 01-0066) |
| ICC Docket 01-0066 (Cook County Motion) | January 22, 2001 | Cook County State's Attorney | Motion challenging 847 exhaust assertion, citing 29 unassignable NXX codes. Requested stay of customer education and order requiring NeuStar to demonstrate exhaustion. (ICC Docket 01-0066) |
| ICC Docket 01-0066 (ICC Staff Response) | February 1, 2001 | Illinois Commerce Commission | ICC rejected NANPA's exhaust notice. Directed NeuStar to reevaluate 847 exhaust status. Prohibited issuing any 224 NXX codes or beginning customer education until reevaluation complete. (ICC Staff Response) |
Demographics & Economics
- Total Population
- 2,999,287
- Population Density
- 1,698 people/sq miabove U.S. average (U.S.: 94 people/sq mi)
- Median Household Income
- $100,678above U.S. median (U.S.: $78,538)
- Poverty Rate
- 10.3%below U.S. average (U.S.: 12.4%)
- Unemployment Rate
- 5.9%above U.S. average (U.S.: 5.2%)
- Education Attainment
- Bachelor's Degree+42.8%above U.S. average (U.S.: 35.0%)High School or Lower27.3%
Statistics are population-weighted aggregations from Census ACS 5-year estimates.See Sources for details.
Geographic Coverage
State
IL
Major Cities
- Chicago
- Elgin
- Waukegan
- Schaumburg
- Evanston
- Arlington Heights
- Palatine
- Skokie
- Des Plaines
- Mount Prospect
- Hoffman Estates
- Glenview
- Buffalo Grove
- Bartlett
- Carol Stream
- Park Ridge
- Streamwood
- Wheeling
- Carpentersville
- Hanover Park
- Northbrook
- Glendale Heights
- Elk Grove Village
- Mundelein
and 96 more cities
Time Zone
- Central Time (CT)
Current Time
County Coverage
Population-weighted county share based on aggregated ZCTA population (100% = total mapped population for area code 224).
| County | Population | Share |
|---|---|---|
| Cook, IL | 1,371,335 | 45.7% |
| Lake, IL | 852,115 | 28.4% |
| Kane, IL | 383,282 | 12.8% |
| McHenry, IL | 209,509 | 7.0% |
| DuPage, IL | 161,202 | 5.4% |
| DeKalb, IL | 21,844 | 0.7% |
Call Context
This area code serves a major metropolitan region with high population density in IL. The primary city is Chicago.
Nearby Area Codes
Area codes geographically closest to 224.
Other Area Codes in Illinois
Area codes that also serve Illinois, linked for easy comparison.
Frequently Asked Questions
Common questions about area code 224 and how phone numbering works.
ICC Docket 01-0066: ICC rejected NANPA's exhaust notice in Feb 2001; Cook County State's Attorney filed motion challenging exhaust assertion.
NANPA/ICC meeting minutes (Jan 11-12, 2001): 29 NXX codes out of 800 designated as unassignable (12 Oddball, 5 Test, 1 Special Use, 1 Reserved, 10 Protected).
Phone numbers assigned to area code 224 are tied to where they were originally provisioned — not the caller's current location. This code serving roughly 2999k people covers Chicago in IL, so a number originally set up there will retain the 224 prefix even if the owner moves or uses VoIP. As a densely populated metro area, Chicago sees high call volume from both local and redirected numbers. Mobile phones keep their original number when users relocate, and businesses often adopt local area codes to establish a regional presence.
Start by looking up the area code on this site to understand its geographic context — area code 224 is associated with Chicago in IL. For caller-specific details, use your carrier's caller ID features or check public directories. If you suspect fraud, you can report it to the FTC. To file a complaint about robocalls or spoofed numbers, visit the FCC Consumer Complaint Center. You can also register with the National Do Not Call Registry.
When an area's available number pool runs low, regulators introduce an "overlay" code covering the same territory. Both codes coexist, and new numbers are assigned from whichever has availability. Area code 224 serves the Chicago region in IL, where growing demand for phone numbers necessitated an additional code. This area code shares its region with area code 847. Learn more in our overlay vs split guide.