Prefix Information
The prefix 340 is part of area code 307 serving Cheyenne, Wyoming.
This exchange contains 10,000 possible phone numbers (307-340-0000 through 307-340-9999).
Phone numbers with prefix 340 in area code 307. Location: Cheyenne, Wyoming.
The prefix 340 is part of area code 307 serving Cheyenne, Wyoming.
This exchange contains 10,000 possible phone numbers (307-340-0000 through 307-340-9999).