The TN visa category is part of the North American Free Trade Agreement (NAFTA). It permits Canadian and Mexican citizens who possess specific required qualifications and credentials to work in the U.S. on a temporary basis in certain defined professional occupations. Canadian and Mexican citizens can be admitted to the United States in TN status in increments of up to 3 years. Extensions of stay are also granted in up to 3-year increments. Status can be renewed indefinitely, provided that the stay remains temporary in nature.