Is an ESTA enough when travelling by land from Canada to US with an RV and back to Canada with the RV?
We have an Esta and are flying to Toronto and back from Calgary Canada.
According to US Customs and Border Protection, you do not even need an ESTA.
If you are a citizen of a country that participates in the Visa Waiver Program (VWP), and you enter the U.S. by land from Mexico or Canada, you are only required to complete the paper I-94W form at the land border crossing. ESTA is currently required for air and cruise ship travel only.
Note: VWP citizens do not need an ESTA to travel on the ferries between Vancouver and Victoria, BC and Washington state. They are treated as a land border port