I will be working in Canada this summer under the "Global Skills Strategy" program. While the invitation letter of the institution hosting me as a "NOC 4012 - Visiting Scholar, Award Recipient" has well defined start/end dates, I would like after the end date of my appointment to spend a couple more weeks in Canada as a tourist. In order to be considered as a tourist after this appointment, I have to physically re-enter Canada. As far as I am aware this can be done at the Niagara Falls Border.
The question though is, after exiting Canada, is there an intermediate zone before the Canada/US border? That is, when exiting Canada do I first need to get rejected from the US border (as I do not hold a US visa nor ESTA) before coming back or once I cross the Canadian border, at once may I return?
I'd appreciate any input and also, any links about entering Canada by land as a European passport holder.
Thanks,