Traveling to US from Canada by car. Are borders open? [duplicate]

Summary: As of November 8, non-citizens can enter the United States via the land border for "non-essential travel" (including tourism) so long as they are full vaccinated. They will not need to provide a negative COVID test before entering the US. You will also need the same documentation to cross the border you did before COVID, e.g., a valid passport, a passport card, an enhanced driver's license, etc.

Most of the information you will need to know is in this FAQ provided by the Department of Homeland Security. Pertinent sections (bolding mine, bold/italics original):

Q. Starting November 8, the US will lift restrictions to fully vaccinated non-citizens. What will change?

A. Title 19 restrictions are still in place. But on Nov. 8, 2021, documented non-citizens who are fully vaccinated against COVID-19 will be able to cross the land borders with Canada and Mexico or arrive in the United States by passenger ferry for non-essential reasons, such as to visit friends or family or for tourism. These travelers are required to be prepared to attest to vaccination status and present proof of being fully vaccinated to a CBP officer upon request. Starting in January, both essential and non-essential travelers will be required to be fully vaccinated.

Q. What are the requirements for travelers entering the United States through land borders?

A. Before embarking on your trip to the U.S., travelers should be prepared for the following:

• Possess proof of an approved COVID-19 vaccination as outlined on the CDC website.
• During border inspection, verbally attest to their travel intent and COVID-19 vaccination status.
• All travelers are reminded to bring a Western Hemisphere Travel Initiative compliant document, such as a valid passport (and visa if required), Trusted Traveler Program card, Border Crossing Card, Enhanced Driver’s License or Enhanced Tribal Card when entering the country. Travelers (including U.S. citizens) should be prepared to present the WHTI-compliant document and any other documents requested by the CBP officer.

Q: Do individuals need proof of a negative COVID-19 test like you do to travel by plane?

A: There is not a COVID-19 testing requirement for travelers at land border ports of entry, however valid COVID-19 vaccination is required for documented non-citizens traveling for non-essential purposes.

Finally, remember that for the return trip to Canada you will need to submit an application in ArriveCAN within 72 hours of crossing the border back into Canada, including proof of vaccination and a quarantine plan. (There does not appear to be a US equivalent of the ArriveCAN app to pre-submit your information before arriving in the USA.) You will also need to take a COVID PCR or NAAT test (not the antigen test) within 72 hours of arriving at the border, and make sure that you have a negative result to present to the border agent by the time you arrive at the Canadian border. Luckily this can often be done free of charge in the United States. For a trip of less than 72 hours duration, it's also allowable to get a test in Canada before you enter the USA:

Canadian citizens, people registered under the Indian Act, permanent residents and protected persons travelling to the United States are allowed to do their pre-entry molecular test before they leave Canada. If your test is more than 72 hours old when you re-enter Canada, you’ll be required to get a new pre-entry molecular test in the United States.

The key is that the test sample must have been collected less than 72 hours; it doesn't matter so much where it was done.