Prefix Information
The prefix 991 is part of area code 231 serving Muskegon, Michigan.
This exchange contains 10,000 possible phone numbers (231-991-0000 through 231-991-9999).
Phone numbers with prefix 991 in area code 231. Location: Muskegon, Michigan.
The prefix 991 is part of area code 231 serving Muskegon, Michigan.
This exchange contains 10,000 possible phone numbers (231-991-0000 through 231-991-9999).