When putting together your documentation for an international trip to Canada, what you need all depends on how you're traveling there. The short answer: A passport never hurts and is always the most official document to bring on an international trip. However, if you're driving or arriving by sea, you don't necessarily need to bring it along.
Travelers can either use an enhanced driver's license, a traveler card (NEXUS, SENTRI, or FAST), or military identification cards when crossing the border into Canada by car or boat. For kids, the rules are a bit different. Children 15 or younger can legally cross the border with parental consent as long as they have a certified copy of their birth certificate, according to the U.S. Department of State.
When flying into the country, the rules are much more clear. Regardless of the point of departure, all travelers need to present a valid passport at arrival, according to U.S. Customs and Border Protection.
So the next time you're planning a family-friendly getaway or a solo trip to the Great White North, make sure to get all of the appropriate documentation in order because if you show up with the wrong papers, your trip will promptly be cut short.