Up until May 31, 2009, Canadian citizens entering the United States by land or water may use a government-issued photo ID, such as a driver's licence, and a birth certificate or a Canadian citizenship card.
Starting June 1, 2009 the U.S. will introduce tighter rules for Canadian and U.S. citizens traveling by land into the U.S. As of that date, Canadians must ensure that they have acceptable documentation to enter the U.S. by land. Passports or NEXUS cards are acceptable. In addition, for entry by land or water (but not by air) the U.S. Western Hemisphere Travel Initiative (WHTI) allows Canadians to use an enhanced driver's licence, which Canadian provinces have been, or will be, introducing. Non-compliant driver's licences will not be acceptable as of June 1.
Canadian citizens who are 15 years of age or under will only require proof of citizenship, such as an original or a copy of a birth certificate, or a Canadian citizenship card, to be able to enter the U.S. by land.
We recommend that any Canadians needing to travel to the U.S. for business purposes, including those entering by land only, should obtain a passport well in advance of any entry.