“This rule finalizes the first phase of a joint Department of Homeland Security and Department of State plan, known as the Western Hemisphere Travel Initiative, to implement new documentation requirements for certain United States citizens and nonimmigrant aliens entering the United States. As a result of this final rule, with limited exceptions discussed below, beginning January 23, 2007, all United States citizens and nonimmigrant aliens from Canada, Bermuda, and Mexico departing from or entering the United States from within the Western Hemisphere at air ports-of-entry will be required to present a valid passport.” 71 Federal Register 226, p. 68412, Nov. 24, 2006.
According to the USCIS’s Frequently Asked Questions regarding the final rule, “U.S. citizens will need a passport to enter the United States by air from Canada, Mexico, Bermuda, South and Central America, and the Caribbean (otherwise known as the Western Hemisphere).
Also under this rule, citizens of Mexico, Canada, and Bermuda will now have to have a passport when entering the United States by air.”