Foreign nationals looking to temporarily work in the United States must apply for a nonimmigrant visa, unless they are visa exempt. To qualify, he/she must have a specific employment offer through a U.S. employer or sponsor. A nonimmigrant visa also has a maximum stay limitation. Depending on the temporary immigration category, a visa can permit a holder to remain in the country for a period that ranges from weeks to several years. The specific requirements for each of the categories differ.