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Quote: TN Canadian or Mexican Citizen under NAFTA
The TN classification applies to a Canadian or Mexican citizen seeking admission as a professional temporarily under the North American Free Trade Agreement.

Petition Document Requirements
For a Canadian citizen:
This classification does not require a petition for employment if the alien is a Canadian citizen and is outside of the U.S. Canadian citizens need not obtain TN-1 consular visas, and may apply directly at Class A U.S. ports of entry. They must provide:

A statement from the employer with a full description of the nature of the duties the beneficiary will be performing, the anticipated length of stay, and the arrangements for pay or reward;
Evidence that the beneficiary meets the education and/or alternative credentials for the activity;
Evidence that all licensure requirements, where applicable to the activity, have been satisfied;
Evidence of Canadian citizenship.
For a Mexican citizen:
This classification does not require a petition for employment if the alien is a Mexican citizen and is outside the U.S. However, Mexican citizens are still required to obtain TN visas at the U.S. consulate abroad. They must provide:
A statement from the employer with a a full description of the nature of the duties the beneficiary will be performing, the anticipated length of stay, and the arrangements for pay or reward;
Evidence that the beneficiary meets the education and/or alternative credentials for the activity;
Evidence that all licensure requirements, where applicable to the activity, have been satisfied;
Evidence of Mexican citizenship;