U.S. Travel Waiver
A United States Citizenship & Immigration Service (USCIS) Travel Waiver is a determination by that agency allowing one to enter the United States despite grounds that would make a person inadmissible. A person who has been previously denied entry or is inadmissible on certain grounds requires a Waiver.

Each Applicant for a Waiver has a unique set of circumstances and each Application is judged on its own merits. There is absolutely no guarantee that an Application will be treated favorably. If an Application is denied you will receive in writing the reason for your rejection and provided the opportunity to appeal. If you are successful your Waiver will be mailed directly to you in 4-12 months time.

Waivers are conditional and are usually good for a period of up to five years.  If you are in the process of renewing a waiver, the process should usually commence at least 9 to 10 months before the expiry of your current waiver depending of the Port of Entry which issued your waiver. 
 The United States Citizenship & Immigration Service currently requires approximately 9 months for processing a Waiver Application.  The US Citizenship & Immigration Service Fee is not refundable and one must wait in Canada while the Waiver request is being processed.