The next season of Top Chef US has been announced as being in "Canada" (with
the promo featuring judge Gail Simmons in her hometown of Toronto). There's been a lot of filming in Toronto apparently, although host Kristen and Gail were posing at Inglewood Drive-In on Kristen's instagram. The way the US show is filmed is typically with a single major location, with one or two episodes filmed doing an excursion nearby during the season and then the last few episodes filmed somewhat later in a completely different location. For example, the most recent season ("Wisconsin") was filmed in Milwaukee; there was a two episode trip to Madison fairly early in the run, and then the finale was filmed on a cruise ship in the Caribbean. Vancouver/Whistler was the finale location of one season (the not-great Texas season). The show does a lot of work on promoting local restaurants and food businesses, and is
underwritten heavily by tourism boards.
My guess is that the main season is set in Toronto, with a couple of day trips (Niagara for sure, perhaps cottage country?), and then Calgary/Banff is either the semi-finale location for the last 6-8 chefs with an overseas finale, or we are hosting the actual finale.
A rumour is that a challenge will involve cooking on covered wagons.