The North American Free Trade Agreement (NAFTA) established a TN (Trade NAFTA) visa classification, which is available only to citizens of Canada and Mexico.
TN status is limited to certain professions stipulated under NAFTA and may be granted in 3-year increments. There is no limit to the number of years an individual may hold TN status, but the employment must be temporary in nature. The TN visa classification is not to be used for tenure-track faculty or permanent staff positions. It is employer and position specific.