Prefix Information
The prefix 340 is part of area code 641 serving Mason City, Iowa.
This exchange contains 10,000 possible phone numbers (641-340-0000 through 641-340-9999).
Phone numbers with prefix 340 in area code 641. Location: Mason City, Iowa.
The prefix 340 is part of area code 641 serving Mason City, Iowa.
This exchange contains 10,000 possible phone numbers (641-340-0000 through 641-340-9999).