Beginning on January 22, 2022, the U.S. Department of Homeland Security now requires non-U.S. individuals seeking to enter the United States from Canada or Mexico by land or ferry to provide proof of full vaccination against COVID-19. These new restrictions apply to non-U.S. individuals who are traveling for both essential and non-essential reasons. They do not apply to U.S. citizens, Lawful Permanent Residents, or U.S. nationals. Children under 18, individuals with medical contraindication, and others falling under limited exceptions are exempt from this requirement. This new policy is in effect until April 21, 2022, unless further extended.
Please see here for additional details: