If you are planning travel to Canada or Mexico, you need to check whether you will need a visa to enter the country. For Canada, check the Canadian government's immigration website. For Mexico, check the website of the Mexican Consulate.
OVIS recommends you apply in your home country, whenever possible. If your application processing is delayed, it is usually preferable to wait in your home country than a third country.
The U.S. Consulates in Canada and Mexico sometimes suspend visa processing operations for third country nationals, so it is important to check in advance.
Speak to your OVIS advisor before planning a trip to Canada or Mexico for your visa application.
After initial entry to the U.S., nonimmigrants who have an expired visa in their passport may re-enter the U.S. without obtaining a new visa if their travel was solely to the contiguous countries of Canada and Mexico. F and J visa holders may also be able to benefit from Automatic Revalidation after travel to the Caribbean Islands (excluding Cuba). Travel must be for a period of fewer than 30 days. This procedure is known as Automatic Revalidation of the U.S. visa.
To take advantage of Automatic Revalidation, travelers must have, in addition to the documents for re-entry stated above, a copy of their electronic I-94 record (or white I-94 card, if you have one).
You can find more information on Automatic Revalidation on the U.S. Department of State website.