Area code 312

Q: Is area code 312 toll-free?

No. Area code 312 is a standard geographic code in Illinois. Toll-free codes in the United States include 800, 833, 844, 855, 866, 877, and 888.

Q: Do I have to dial the area code for local calls in 312?

Yes. Because 312 is overlaid with 872 (and shares the city with 773), 10-digit dialing is required for local calls. Mandatory 10-digit dialing has been in effect since 2009.

Q: Which states and cities use the 312 area code?

Illinois. 312 serves the City of Chicago's central area, including the Loop, Near North Side, West Loop, and South Loop.

Q: Can I keep my 312 number if I move or switch to a service like Sideline?

In most cases, you can keep your existing number when you move. You can usually port your existing 312 number to Sideline when available, but verify with your provider before starting the port-out.

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312 area code

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About the 312 Area Code

Where the 312 area code covers

The 312 area code covers central Chicago in Illinois, including downtown neighborhoods such as the Loop, Near North Side, West Loop, and South Loop.

Overlays for the 312 area code

The 312 area code is overlaid by 872 and works alongside 773 in the rest of the city. The 872 overlay began service in 2009, bringing 10-digit dialing to all local calls across the 312/872/773 region.

Time zone for the 312 area code

The 312/872/773 region follows Central Time (CT), observing daylight saving time like the rest of Chicago.

Interesting facts about the 312 area code in Illinois

Chicago is widely regarded as the birthplace of the modern skyscraper and is globally admired for its architecture.
The Loop is Chicago's central business district, named after the elevated "L" train tracks that loop around downtown.
Willis Tower (formerly Sears Tower) was the world's tallest building from 1973 until 1998.
In 1900, engineers reversed the flow of the Chicago River to protect the city's drinking water supply
O'Hare International Airport is consistently ranked among the world's busiest in terms of aircraft movements.
The Art Institute of Chicago and the Field Museum anchor Chicago's museum campus in the downtown area.
Navy Pier is one of the most visited lakefront attractions in the Midwest.
Chicago hosts major professional sports teams across baseball, basketball, football, and hockey.

FAQs about the 312 area code

Is area code 312 toll-free?

No. 312 is a standard geographic code in Illinois. U.S. toll-free codes include 800, 833, 844, 855, 866, 877, and 888.

What time zone does area code 312 use?

It uses Central Time (CT), shifting between CST and CDT with daylight saving.

Do I have to dial the area code for local calls in 312?

Yes. Because 312 is overlaid with 872 (and shares the region with 773), 10-digit dialing is required for all local calls. This has been mandatory since 2009.

Which states and cities use the 312 area code?

Illinois, specifically the central downtown part of Chicago, including the Loop, Near North Side, West Loop, and South Loop neighborhoods.

Can I keep my 312 number if I move or switch to a service like Sideline?

In most cases, yes, you can keep or "port" your 312 number when moving or switching to a service like Sideline - just check with your provider first to make sure number portability is available.

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