OBTAINING A VISA
Generally, a citizen of a foreign country who wishes to enter the United States must have a valid passport and obtain a visa from the U.S. Department of State. Travel resources on the State Department's official website — usvisas.state.gov — provides the latest requirements and more detailed information.
Visitor visas are nonimmigrant visas for persons who want to enter the United States temporarily for business (visa category B-1); tourism, pleasure or visiting (visa category B-2); or a combination of both purposes (B-1/B-2).
The Visa Waiver Program (VWP) allows citizens of participating countries (there are currently over 30 including Australia, Belgium, France, Germany, Ireland, Japan, Netherlands, Spain, UK) to travel to the United States without a visa for stays of 90 days or less, when they meet all the listed requirements and are approved through the Electronic System for Travel Authorization (ESTA).
Citizens of Canada and Bermuda visiting the United States for temporary travel do not require a nonimmigrant visa, except in certain circumstances. The Western Hemisphere Travel Initiative requires that travelers from the Caribbean, Bermuda, Mexico and Canada have a passport or other secure, accepted document to enter or re-enter the United States by air, land or sea.
The Transportation Security Administration (TSA) provides travelers with all they need to know before boarding a plane to or within the U.S.
U.S. Customs and Border Protection (CBP) is the unified border agency charged with the management, control, and protection of U.S. borders at and between the official ports of entry. The CBP sets restrictions on commercial and personal items that can be brought into the United States.
CBP's Trusted Traveler Programs — which include Global Entry, NEXUS and SENTRI — provide expedited travel for pre-approved, low risk travelers through dedicated lanes and kiosks.