Prefix Information
The prefix 521 is part of area code 779 serving Rockford, Illinois.
This exchange contains 10,000 possible phone numbers (779-521-0000 through 779-521-9999).
Phone numbers with prefix 521 in area code 779. Location: Rockford, Illinois.
The prefix 521 is part of area code 779 serving Rockford, Illinois.
This exchange contains 10,000 possible phone numbers (779-521-0000 through 779-521-9999).