Scientists traveling to the United States are advised to apply for a visa as early as possible (at least three months or more before visa is needed). To determine the earliest that you may apply for a visa, please check with your local consulate or embassy. Because of the number of visas being processed and the need for thorough review, visa processing can take 8 weeks or longer, especially for those countries that are on the State Sponsors of Terrorism List. Attendees from these countries should start the application process at least 6 months or more in advance of the course.