TN status is initially granted for up to 3 years.
Extensions of stay may be granted in increments of up to three years. Employees will need to demonstrate that they do not intend to reside permanently in the US.
Use caution if you are pursuing a stay of longer than 6 years. DHS may deny your application (or re-entry into the US at the border) or require further proof of the temporary nature of your employment.
TN employees may enter the U.S. up to 10 days prior to the start date indicated in the TN Employment Letter or I-797 approval notice if a petition was filed. There may also be a discretionary 10-day grace period after the employment end date indicated on the I-94. To confirm if the grace period was granted, check the I-94 each time you re-enter the United States. You cannot work during the grace period.