The 224 area code, an integral part of Illinois' telecommunications system, was established to address the increasing demand for phone numbers, particularly in the Chicago metropolitan area.

Implementation as an Overlay: The 224 area code was introduced as an overlay to the existing 847 area code. This implementation, effective March 5, 1996, was designed to provide additional numbering resources in the region, ensuring a continuous supply of telephone numbers. The overlay approach allowed existing 847 subscribers to retain their phone numbers, while new numbers could be assigned either the 847 or 224 area code.

Geographical Coverage: The 224 area code, along with its parent 847 code, covers the northeastern region of Illinois, including parts of the Chicago metropolitan area. It encompasses northern and northwestern suburbs of Chicago, including cities like Schaumburg, Evanston, and Des Plaines. This area is characterized by a mix of urban and suburban communities, reflecting the diverse demographic and economic landscape of the region.

Adoption of Ten-Digit Dialing: With the introduction of the 224 overlay, ten-digit dialing became mandatory for all local calls within the 847 and 224 area codes. This requirement, which necessitates dialing the area code followed by the seven-digit phone number, aligns with the standard practice in regions with overlay area codes across the United States. The change was essential to accommodate the growing number of phone users and the consequent need for more telephone numbers.

These facts about the 224 area code highlight its vital role in supporting the telecommunications needs of the Chicago metropolitan area. By providing additional numbering capacity and facilitating the transition to ten-digit dialing, the 224 area code ensures that the region's communication infrastructure can keep pace with its growth and evolving needs.