[guan]

The situation is similar for ESTA and travel to the United States. ESTA is required for travel by plane and ship, but not over land. If you are planning to apply for admission to the US under the visa waiver program at a crossing of the land borders with Canada or Mexico, you don’t need ESTA.

(There are a few ferries between British Columbia and Washington state that are also treated as a land border.)

[ketzu]

Interesting, I misunderstood the info I got while traveling there. The way the border agents phrased it I required esta as well as an additional form, but the website I checked now says I wouldn't have needed the esta as you said!

For me, arriving at the US by land was by far a worse experience than arriving by air, as my passport was taken until they had time to process me, waiting in a room i was not allowed to leave, then filling out an additional form and paying additionally. Contrasted to arriving by air "do you have esta? -> yes -> have fun" at the immigration.