- Centers for Disease Control and Prevention - Specific health information, required vaccinations for travel.
- Foreign Consular Offices in the United States - U.S. citizens and non-U.S. citizens can contact foreign consular offices for more information on required documentation for entry into a specific country.
- U.S. Citizenship and Immigration Services - Travel document and re-entry permit information for non-U.S. citizens.
- U.S. Customs & Border Protection - U.S. travel alerts, entry and exit policies, prohibited and restricted goods.
- Western Hemisphere Travel Initiative - For travel between the United States and the Caribbean, Latin America, and Canada.
- Yale and the World website