US Passport Control In Canada Question
 

The last few times I left Toronto, I stood in the long USA passport control line at the Toronto airport - followed by a brief customs control visit. It is a very annoying experience and there doesn't seem to be any way (e.g, priority lane) to shorten the experience. My question is if one originates a flight in Quebec City, then connects in Toronto to return to the USA, where does one go through USA passport control? Logically (and unfortunately), it appears it would be Toronto but I am wondering if someone can confirm that - or tell me differently. I am hoping it is QC but if it is Toronto, does one have to enter USA passport control in the same manner as travelers originating in Toronto and flying back to the USA?

" ... one originates a flight in Quebec City, then connects in Toronto to return to the USA, where does one go through USA passport control?"

Toronto.

If you cross the Canada/US border often, you might look into Nexus, which can significantly reduce you time crossing the border.

Toronto or Quebec City????????????????

You go through US border control in Toronto.