Western Hemisphere Travel Initiative

The Western Hemisphere Travel Initiative (WHTI) is a United States legal framework from 2007 that requires all travelers to show a valid passport or other approved secure document when traveling to the U.S. from areas within the Western Hemisphere. The purpose, according to the U.S. Department of State and U.S. Department of Homeland Security, is to strengthen border security and facilitate entry into the United States for both legitimate U.S. citizens and foreign visitors. The initiative is an outcome of the Intelligence Reform and Terrorism Prevention Act, which was approved after the 9/11 (2001) al Qaeda mass-terror attacks on the US. The Western Hemisphere Travel Initiative was also implemented to deter or prevent the use of forged documents, both for terror and criminal purposes.

US or Canadian citizen children under age 16 (or, when traveling as part of certain groups, under age 19) can also use other documents as identification, including a birth certificate, for land and sea border crossings.

Native Americans in the United States, Mexico, and Canada may be able to use certain additional forms of identification (in addition to the documents valid for citizens of those countries):

In addition to the other documents designated under WHTI, U.S. citizens on round-trip cruise-ship voyages that begin and end at the same port of entry in the United States may also carry a government-issued photo ID and birth certificate, Consular Report of Birth Abroad, or Certificate of Naturalization. Foreign nationals need a WHTI-designated document to travel to the United States on a cruise ship.

The U.S. Department of State names the following jurisdictions:

Anguilla
Antigua and Barbuda
Aruba
Bahamas
Bermuda
British Virgin Islands
Canada
Caribbean Netherlands
Cayman Islands
Curaçao
Dominica
Dominican Republic
Grenada
Jamaica
Mexico
Montserrat
Saint Kitts and Nevis
Saint Lucia
Saint Vincent and the Grenadines
Sint Maarten
Turks and Caicos Islands