Originally Posted by nandu
Passport is always necessary to cross the border whether you are going for holiday trip or for any business tour.It is necessary for children/elders and all.Without passport you will not be allowed to cross any border.
Definitely not true.
If you're going from the USA to Canada or Mexico via car or train, you can use Passport Cards and don't need a Passport.
If cruising, often a Passport or Passport card is NOT required, but then you must have an original birth certificate along with a government issued photo ID, such as a driver's license, unless you're a minor travel with your parents, in which case you'll still need the original birth certificate.
However, when cruising to Canada or cruising out of Canada, then passports are required.
Each specific situation is different and what applies in one situation is not necessarily true for another situation, which is why it's important to talk to your travel agent and NEVER assume the type of documentation you'll need.