Originally Posted by
kenwood
As a Canadian, I will be traveling to the US for work every week for 6 weeks. Do I need to get a TN Visa? Or is a company letter sufficient?
If you're coming here to do business (business meetings, etc.) you're exempt because you are from a visa waiver nation.
If you come here to "work": Visa.
"All foreign workers must obtain permission to work legally in the United States."
"Nonimmigrants enter the United States for a temporary period of time, and once in the United States, are restricted to the activity or reason for which their nonimmigrant visa was issued."
http://www.uscis.gov/working-united-states/working-us
Some might argue this doesn't apply if you speak Spanish, but then we'd have to move the thread.