Google is your friend. I've no idea if this place are any good, but looking for 'ontario' and 'brazilian jiu jitsu' immediately brings up Joslin's Martial Arts. Their BJJ is affiliated with Alliance BJJ (Jacare's organisation), so I presume thats a plus in their favour.
Yeah, I've used google and found plenty of resources that list BJJ schools in Ontario, but so far I haven't found one in Peterborough... and that's kind of a key detail, since next september I'll be moving there, so I'd like to be able to keep up with my training.
If you're not able to travel, then you'll probably have to settle for judo instead. Good style to cross-train with BJJ anyway.