Basically speaking, upon arrival in the U.S. travelers must present a passport that has at least 6 months of validity remaining after the planned departure date. The United States, however, has concluded agreements with numerous countries that suspend this requirement. These countries are members of the so-called Six-Month Club, which allows nationals of the said countries to enter the USA with a passport which is valid only for the duration of the stay. Germany, Austria, and Switzerland, for example, are participating countries. The U.S. Custom and Border Protection provides a complete list of countries.