A visa is only required for United States citizens to enter Canada if the stay is going to last more than six months.
A current passport is an acceptable form of identification for United States citizens wanting to cross the U.S.-Canadian border.
If a resident of the Untied States does not have a valid U.S. passport, an enhanced driver's license--a license issued by some states that indicates both identity and citizenship status--can be used to enter Canada.
The legal document that children who are traveling without their parents or guardians need to cross the U.S.-Canadian border is a notarized letter that states proof of custody or authorization for travel plans.
A dog or a cat can only be brought across the border if it is accompanied by a rabies certificate that has been signed by a licensed veterinarian. There are certain exceptions for dogs, such as seeing-eye dogs.
