US citizens require a visa for visiting the following countries: Afghanistan, Algeria, Angola, Australia, Azerbaijan, Bahrain, Benin, Bhutan, Burundi, Cameroon, Chad, China, Congo, Cuba, Eritrea, Gambia, Ghana, Iran, Iraq, Libya, Mali, Nauru, Niger, Nigeria, Russia, Sudan, South Sudan, Syria, Turkmenistan, Uzbekistan, Venezuela, Vietnam, Yemen
They can obtain a visa on arrival for the following countries: Azerbaijan, Bangladesh, Burkina Faso, Cambodia, Egypt, Ethiopia, Gabon, Guinea-Bissau, Jordan, Kenya, Kuwait, Laos, Madagascar, Malawi, Mauritania, Mozambique, Nepal, Paraguay, Rwanda, Saudi Arabia, Sierra Leone, Somalia, Sri Lanka, Tanzania, Timor-Leste, Togo, Tonga, Tuvalu, Uganda, United Arab Emirates, Zambia, Zimbabwe.