In an effort to prevent runaways and abductions in British Columbia and other provinces, there are strict laws at both the U.S. and Canada border posts. U.S. immigration officials will require certain documents to prove that minors are travelling across the border with the consent of parents or guardians. This applies to unaccompanied minors that travel without their parents or guardians.
Special border regulations are in place for children who are 15 years old or younger -- they are regarded as minors. If they travel alone, they will need to present a valid passport for both air travel and crossing borders by sea or land. However, additional documents could serve the identification purpose for minors entering the United States by sea or land. These include a Naturalization Certificate, a Consular Report of Birth Abroad or a Canadian Citizenship Card.
Furthermore, any minor crossing the U.S. border must present a consent letter signed by both his or her parents. Information on the letter must include the names, contact details and addresses of both parents, along with similar details of the adult in whose care the minor will be in the United States. If only a single parent is listed on the consent form, proof must be provided that shows that only that parent is responsible for the minor child. Similar proof will be required when a guardian signs the letter.
British Columbia parents who are planning to send their minor children across the border unaccompanied may find it helpful to discuss the matter with an experienced lawyer who deals specifically with U.S. immigration and people travelling from Canada to the U.S. The lawyer can explain all the requirements and make sure that all documentation is in order. This could prevent circumstances in which an unaccompanied minor is held up at the border due to insufficient documentation.
Source: USA Today, "What Documents Does a Minor Traveling Alone Require to Leave Canada & Return?", Accessed on Sept. 15. 2017