Effective June 1, 2009, U.S. citizens returning to the United States from Canada, Mexico, the Caribbean or Bermuda, by land or sea, will be required to present an approved travel document to be admitted to the United States.

A complete list of Western Hemisphere Travel Initiative-compliant documents appears on the Department of Homeland Security Web site at: http://www.dhs.gov/xtrvlsec/crossingborders/