Entering Canada from the US

It is not necessary for US citizens to have a passport to enter Canada or return to the US, although having one may make things speedier at the border. Here is an excerpt from the Citizenship and Immigration Canada website.

Arriving in Canada

Customs officers are at the border to ensure that people entering Canada respect Canadian laws. They are authorized to interview persons seeking entry to Canada to determine admissibility. Their goal is to facilitate the entry of legitimate travellers as quickly as possible.

When you enter Canada, a customs officer may ask to see your passport and a valid visa, if one is necessary. If you are a citizen of the United States, you do not need a passport to enter Canada. However, you should carry proof of your citizenship, such as a birth certificate, certificate of citizenship or naturalization, as well as a photo ID. If you are a permanent resident of the U.S, you should bring your Permanent Resident Card (i.e., green card) with you.

Bringing children into Canada

If you are travelling with children, you should carry identification for each child. Divorced parents who share custody of their children should carry copies of the legal custody documents. Adults who are not parents or guardians should have written permission from the parents or guardians to supervise the children. When travelling with a group of vehicles, parents or guardians should travel in the same vehicle as the children when arriving at the border. Customs officers are looking for missing children and may ask questions about the children who are travelling with you.

More information for visitors to Canada is also available on the Canada International website (http://canadainternational.gc.ca/gtc/NeW-Visiting_Canada-en.aspx)