Hello:

If you are asking what immigration documents are needed to move to the U.S., please advise. In that case I can ask to move your question to a U.S. law expert.

But if you want to know about the family law requirements for moving your child:

If you have legal custody, then you do not need any other document. It would be best in crossing the border if you have a copy of the order or the agreement that indicates that you have custody. Likely with a 16 year old confirming the custodial arrangements is not even going to be an issue to any border officials. But having sole custody gives you the ability to decide where a child will live.

You do have an obligation to give 30 days notice to the other parent, if he has access to your child, that you intend to move out of the province. The other parent does have the ability to apply to court to try and seek an order preventing the child from moving out of the province. Most such applications are unsuccessful, as courts generally give considerable weight to the viewpoint of a custodial parent and the right such a parent has to live where he or she chooses. Also, if a child at age 16 is agreeing to move with their parent, and that child has a typical level of maturity for a child of that age, most courts will see no point to interfering with those wishes.

The court order regarding child support would remain in effect. The court in Ontario will continue to have jurisdiction as long as the father resides here, and so you can apply back to the Ontario court annually for a review of child support, if the income of the father increases for example and so the amount of child support payable should also increase.