A passport is an internationally recognized travel document that verifies the identity and nationality of the bearer. Only the U.S. Department of State and U.S. Embassies and Consulates have the authority to grant, issue, or verify U.S. passports. For travel overseas and to facilitate reentry into the U.S., a valid U.S. passport is the best documentation available.
A valid passport is required to enter and leave most foreign countries.
Some countries may allow you to enter with only a birth certificate, or with a birth certificate and a drivers license. Note, however, that rules established under the U.S. Intelligence Reform and Terrorism Prevention Act of 2004, require that all persons, including U.S. citizens, traveling by air, must present a valid passport to reenter the United States. (Until September 30, 2007, U.S. citizens who have applied for but not yet received passports can enter and depart the United States by air to Western Hemisphere countries with a government-issued photo identification and official proof of application for a passport. This accommodation does not affect entry requirements of other countries, and U.S. citizens who are traveling to...