312 Area CodeChicago, IL

Overview of the 312 Area Code

What cities does area code 312 cover?

City population is shown in full. The share of each city inside 312 is measured from Census tract centroids, not estimated from a rate-center match – so a city split between two codes appears on both, at the fraction each one actually holds. The “% of listed-city population” column uses the full populations of the cities listed here.

What counties does area code 312 cover?

348,013 residents across 1 county, counted inside the 312 boundary — a county split between codes contributes only its part.

Has area code 312 been reported for unwanted calls?

Yes – 916 unwanted-call complaints were reported to the FTC for numbers showing a 312 area code (May 29 – Aug 14, 2026).

• 53% robocalls
• ↓ 5% vs prior period

Caller ID is easily spoofed, so these figures reflect the number shown on caller ID, not the caller's true location – an area code alone never identifies a caller. The FTC does not verify the facts in these complaints. Source: FTC Do Not Call (DNC) Reported Calls Data, retrieved 2026-08-17.

Which prefixes and exchanges belong to area code 312?

78% assigned to a telco

• 70% Landline
• 30% Wireless
• 0% Unknown

Frequently Asked Questions about the 312 Area Code