TN (Trade NAFTA) status is a special non-immigrant status in the United States unique to citizens of Canada and Mexico.
It allows Canadian and Mexican citizens the opportunity to work in the US in certain professional occupations. It bears a similarity, to the H-1B visa, but also has many unique features.
Within the TN set of occupations, an American, Canadian or Mexican can work for up to three years[1] (until October 16, 2008, one year) at a time. However, the TN status may be renewed indefinitely in three-year increments, although it is not a “permanent” visa and if US immigration officials suspect it is being used as a de facto green card, they may elect to deny further renewals. The set of occupations permitted to petition for TN status is also much more limited than for the H-1B visa.
Spouse and dependent children of TN professionals can be admitted into the United States in the TD status.