The 312 area code covers downtown Chicago, Illinois. It covers the Chicago Loop and surrounding areas of the city of Chicago. It is roughly bounded by North Avenue on the north, Ashland Avenue on the west, Lake Michigan, on the east, and 31st Street on the south. By land area, it is one of the smallest area codes in the nation, encompassing only a few square miles.
The rest of the city of Chicago is in area code 773, and the new 872 overlay area code serves the entire city.
The country code and area code of Mhlume, Swaziland is 268, 312.
The country code and area code of Sawakin, Sudan is 249, (0)312.
The country code and area code of Ankara, Turkey is 90, (0)312.
The country code and area code of Uzhhorod, Ukraine is 380, (8~0)312.
The country code and area code of Colima- Col., Mexico is 52, (01)312.
The country code and area code of San RamÌ_n, Uruguay is 598, (0)312.
The country code and area code of Gyumri- Shirak province, Armenia is 374, (0)312.
The country code and area code of Baoding- HEB, China is 86, (0)312.
The 312 area code is used for downtown Chicago. It is is unusual in that it is completely surrounds by another area code which is 773 and covers the rest of Chicago.
Area code 312 is downtown Chicago. It includes the Chicago Loop and the immediate area around it. The 312-273 prefix is mostly for wireless users (cell phones), but may also include some landline numbers. Area code 773, which serves the rest of Chicago, completely surrounds area code 312; area code 872 is an overlay on both 312 and 773, serving the entire city of Chicago, but not the suburbs.
US area code 872 is Chicago, IL, overlaying 312 and 773.
Area code 312 is located in the Central Time Zone.