From Passport canada:
By land or water
Canadian citizens
will require a passport to enter the United States at land and marine ports of entry as of
June 1, 2009.
However, as of
January 31, 2008, if you travel to the United States by land or water, a United States law requires you to present:
- a government-issued photo ID, such as a driver's licence
AND a birth certificate or a citizenship card;
OR
- for persons aged 18 and under, a birth certificate or a citizenship card only;
OR
- a valid passport.