About 115 miles to the Canadian side... about a 90 min-2 hour drive on I90.
I would say more like 3 hours. I've driven there several times. Buffalo is about an hour and a half way and Niagara Falls is about another hour to hour and a half past Buffalo. Depends on traffic obviously. For a scenic route that you can see more of the 'coast', I would recommend to take Route 5 (however that would take a lot longer, like an hour probably).
About 2 hours.
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