Children under the age of 16 do not need photo identification to enter Canada. They do, however need a valid United States birth certificate or certificate of naturalization.
If the minor that you are traveling with is your child but you do not have full custody of the child, you may be required to provide a notorized affidavit signed by the other party with whom you share custody. This affidavit should include the dates of travel, name and phone number where the other guardian or parent can be reached and their address. You will also need the child's birth certificate or certificate of naturalization.
If the minor child that you are traveling with is not your child, you may be asked to provide a notorized affidavit of permission from the child's parents or guardians, as well as the child's birth certificate or certificate of naturalization. The affidavit should include dates of travel, names, addresses and phone numbers where the parents can be reached as well as a photocopy of the parents' or guardians' state-issued photo identification.
If the child that you are traveling with is your child and you have full custody, you may be required to produce the legal custody papers along with the child's birth certificate or certificate of naturalization.