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

Learn more about overlay and split area codes →

Demographics & Economics

Total Population: 293,470
Population Density: 5,488 people/sq mi
above U.S. average (U.S.: 93 people/sq mi)
Median Household Income: $81,797
near U.S. median (U.S.: $75,144)
Poverty Rate: 13.3%
above U.S. average (U.S.: 11.5%)
Unemployment Rate: 6.9%
above U.S. average (U.S.: 3.6%)
Education Attainment: Bachelor's Degree+
41.9%
above U.S. average (U.S.: 33.7%)
High School or Lower
28.4%

Statistics are population-weighted aggregations from Census ACS 5-year estimates. Population figures are approximate — see Sources & Methodology for details on how area code populations are derived.

See how this area code compares to all US area codes in the income ranking and density ranking.

Time Zone

Central Time (CT)

NANPA Relief Status

According to the latest NANPA analysis (July 2026), this area code is not currently listed as exhausting within the next 36 months. No relief planning is in progress for this NPA.

Source: NANPA NPA Relief Planning Reports · See all relief planning statuses

Current Time

Central Time (CT)

Prefix Utilization

Geographic Coverage

State

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

Area Code 224 geographic coverage map (light mode)

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.

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

Year	Event	Docket	Regulatory Action & Impact
May 1998	Adopted thousands-block number pooling and all-services overlay as backup...	ICC Docket 97-0192	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)
Jun 1998	Published planning letter establishing the overlay of 847 with 224...	NANPA PL-127	Published planning letter establishing the overlay of 847 with 224 (superseded by PL-NANP-109). (NANPA)
Dec 1998	Directed carriers to report individual number utilization rates, mandated...	ICC Docket 98-0497 (Final Order)	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)
Feb 1999	Clarified that NANPA must give the Commission and interested parties at...	ICC Docket 98-0497 (Rehearing)	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)
Jan 2001	NANPA formally notified ICC that 847 NPA was exhausted	ICC Docket 01-0066 (NANPA Notification)	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)
Jan 2001	Motion challenging 847 exhaust assertion, citing 29 unassignable NXX codes	ICC Docket 01-0066 (Cook County Motion)	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)
Feb 2001	ICC rejected NANPA's exhaust notice	ICC Docket 01-0066 (ICC Staff Response)	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)