Yes, you do need a passport to go to Canada or Mexico.
But you could just go to the American side of the falls if you don't want to get a passport.
uote=leatheflea]A week on the Clarion river in PA. No phones, no electricity, no running water(except in the river). We've also talked about going up to Niagra falls. but I think I might need a passport to get into canada, Does anyone know?[/quote]