US says you must be fully vaccinated to enter and show proof upon request.
Fact Sheet: Guidance for Travelers to Enter the U.S. at Land Ports of Entry and Ferry Terminals | Homeland Security
Beginning May 12, 2023, DHS will no longer require non-U.S. travelers entering the United States via land ports of entry and ferry terminals to be fully vaccinated against COVID-19 and provide related proof of vaccination upon request. DHS intends to rescind these Title 19 travel restrictions in...
www.dhs.gov