Where is this area code? On January 1, 1947, the first North American area codes were issued in regions where standard 7 digit dialing codes were scheduled to be exhaused the soonest. ... US Area Codes By State. States Area Codes Missouri 314, 417, 573, 636, 660, 816 Mississippi 228, 601, 662 Montana 406 North Carolina 252, 336, 704, 828, 910, 919
