DUB -> YYZ -> IND
 

I am flying from Dublin to Indianapolis in August for a work trip and have a layover in Tornto. I am having a hard time finding out where I would go through US Customs/Immigration. In the past, I have always done it in Dublin on my return flight when coming back to the US through a US city; however, one of the flights being offered routes through Toronto before coming back to Indianapolis. Would I have to go through US Customs/Immigration in Toronto instead of Dublin? There is only a 1.5 hour layover in Toronto, so that makes me a little nervous that I wouldn't have enough time to make my connecting flight.

Toronto..Definitely

It is, aparently, a legal connection. If you have carry-on only, there's a good chance you'll make it. If you have checked luggage, the odds go down.

You're connecting from Air Canada internation to Air Canada trans-border. When you leave the plane, follow the signs for Trans-border. If you have carry-on only, there's a quick passport check by Canada, and then you go directly to the hall for US customs/immigration. But if you have checked luggage (and unless the system has changed), you have to wait in a holding area for your bags, and it often takes a L-O-N-G time for them to arrive, as they have to separate the Trans-border bags from all the rest.

<i>You're connecting from Air Canada internation to Air Canada trans-border. When you leave the plane, follow the signs for Trans-border. If you have carry-on only, there's a quick passport check by Canada, and then you go directly to the hall for US customs/immigration.</i>

After this you then have to go through the US security check. This is typically the bottleneck in the whole process.

Thanks for the feedback! The business trips are short enough that I have been carrying on my luggage, and I have US global entry clearance to get through US customs quicker, so I'm thinking I should have enough time.