Argh! Need help to resolve travel argument

[Gigi22]

I should know this, but I can't recall what the current procedures are. We are flying from Ottawa to Toronto to U.S. Where do we go through U.S. Customs and Immigration? Ottawa or Toronto? Both airports can do pre-clearance for travel to US. Thanks!

 

[minnie mum]

You will preclear customs in Toronto before you board your connecting flight.

 

[Maddysdaddy]

Are you changing planes in Toronto? If so, then you will clear customs there. If Toronto is just a stop to pick up additional passengers on the same flight, I 'think' you will clear in Ottawa (can't say that with 100% certainty).