Currently (October 9, 2007), if you are traveling to Canada from the United States by land or sea, citizens of USA and Canada do NOT need a passport.  You simply need a government issued photo ID (like a driver's license or other) and your birth certificate or some proof of citizenship (like a citizenship card, etc.).  Depending on the customs officer will depend on how strict they will be about this.  In other words, if you only have your driver's license and nothing else they still may let you pass but it is at the discretion of the officer.  They may otherwise not let you into the country (or you may wait a while if you're entering your own country while they verify your info). So in general - you need to bring a photo ID and proof of citizenship to enter into Canada and back into the USA.  Anything less and you are taking a risk.

ONLY if you are traveling by air are you required to have a passport or something of the equivalent to fly in or out of the United States by air.

Please read below for further details...

Passport Requirements for Air Travel

All citizens of the United States, Canada, Mexico, and Bermuda are now required to present a valid passport when entering the United States at any airport as of January 23, 2007.  This includes:

  • Children of any age, including children of Legal Permanent Residents who are United States citizens.
  • Mexican citizens who have a Border Crossing Card (BCC) when entering the United States by air. (The BCC is still valid in lieu of a passport and visa for land border crossings within the border region.) The BCC may be used as a visa.

Other Acceptable Documents

In some cases, other documents may be accepted when entering or re-entering the United States by air.

A limited number of travelers may present either:

Presenting Insufficient Documentation

For the general public, people who apply for entry but do not have appropriate documentation will likely be referred for secondary screening at the port. In secondary, Customs and Border Protection (CBP) officers will evaluate any evidence of citizenship or identity the individual may have and will verify all information against available databases.

For foreign nationals, a determination will be made at that time whether to admit the individual or not. However, to prevent delay at the ports of entry, it is encouraged that all travelers to obtain the appropriate documents before they travel.

In addition, the State Department has processes to assist U.S. citizens overseas to obtain emergency travel documentation for those with lost or stolen passports.

For further information on what to expect when crossing the border, see Inside Canada: Crossing the Border here at TripAdvisor.