The countries that require a visa for US citizens vary depending on the destination. While not all countries require visas for American travelers, many do. The US State Departments Learn About Your Destination search tool provides information on entry, exit, and visa requirements for each country. Some countries that require a visa for US citizens include Australia, Bolivia, China, India, Russia, and Vietnam. The requirements for obtaining a visa can vary depending on the country, and some countries may require additional documentation beyond a passport. It is important to check the visa requirements for your destination well in advance of your trip to ensure that you have enough time to obtain the necessary documentation.