If you are FLYING into Canada from any country in the world, you MUST have a passport. This goes for infants and children as well. Passports are issued by your country of citizenship Americans can visit the following link for details on how to apply: ...
If you have a passport, you can use it to cross at a land border into Canada. Any American citizen from any state can also drive into Canada using a Passport Card. https://travel.state.gov/content/travel/en/passports/need-passport/card.html or a ...