As of June 1, 2009 both Canadian and US travellers entering the USA by land or water must present a passport or other document that clearly indicates their identity and citizenship. (This went into effect for air travellers in 2007.)
This enhanced requirement is a result of the Western Hemisphere Travel Initiative (WHTI) and its purpose is two-fold: to make it easier for US citizens and foreign visitors to enter the United States while also increasing US border security.
If you currently hold a valid passport you’re okay. However, if you’ve relied on showing a driver’s licence or a birth certificate, or giving a verbal declaration of citizenship, those days are numbered. (There are exceptions for children and youth under 18. Click here for further info.)
This US government site provides valuable information for both Canadians and Americans in terms of travel requirements. When the link opens, simply click on the map and it will show you your options. Some provinces, for example, have begun issuing enhanced driver’s licenses or enhanced ID cards. There are also special programs like NEXUS or FAST/Expres that require pre-enrollment. It may take several weeks to get the required documentation, so apply well ahead of your trip.
Bottom line? Make sure you have approved identification and don’t leave home without it. .