Area Code 312

Local Presence for Chicago, Wheeling, and Northbrook

You can increase your connection rate up to 30% by dialing from a local number.

Local Presence by Tenfold gives you one-click access from your existing phone system to a local number in the US area code 312 and more than 200 others.

Reach out to customers in Chicago, Wheeling, and Northbrook.

Source: Wikipedia