Area code 312 is a telephone area code in the North American Numbering Plan for the city of Chicago, including downtown, the Chicago Loop, and its immediate environs.

Area code 312 is located in Illinois. Get the area’s map, cities covered, current time, prefixes, and dialing instructions.

Jan 1, 2026 · 312 Area Code located in Illinois, including 16 cities, 3 counties, 1 time zone, map, Census demographics, and 778 active prefixes.

2 days ago · 312 is an area code located in the state of Illinois, US. The largest city it serves is Chicago. Find out where 312 area code zone from, which states, counties and cities it covers. Get the most …

Find 312 area code details including city, time zone, and map. Lookup area code 312 phone number, name, and location.

Nov 22, 2025 · Area code 312 is in Illinois, USA , serving the city of Chicago (downtown area); it currently uses 784 prefixes , assigned from 312-200-XXXX through 312-999-XXXX.

About area code 312: location, common spam callers, related area codes, and more. Includes 312 reverse phone lookup to identify spam callers.

The 312 area code is a geographic telephone area code serving downtown Chicago and the immediate surrounding areas in Cook County, Illinois. Established in 1947 as part of the original North American …

Where is Area Code 312? The 312 area code is located in the state of Illinois . 312 is one of the 357 three-digit telephone area codes in the USA. It covers roughly 1,052,188 unique phone numbers and …

Area code 312 serves the heart of Chicago, Illinois, covering downtown and nearby neighborhoods along Lake Michigan. It includes the city’s core business and cultural districts, such as the Loop, …