here's what I found closest to montreal on the south shore:
CAMPING AMÉRIQUE MONTRÉAL

CAMPING DOMAINE DU BEL ÂGE

and this on about 30 mins out west but great diving/spearfishing area...

CAMPING KOA MONTRÉAL-OUEST


good luck

just saw your message.. let me get back to you asap

Hey Man, summer is imminent!! I'm going to Quebec because one of my singing students has a job performing with Queen Extravaganza, Jennifer Espinoza is scheduled for her third 'gig' with Brian May and Roger Taylor's project band.
So I am stoked that most of the shows are in Quebec, because
I am determined to eat Walleye every day!
However, I am on a budget so I want to camp near the St.
Lawrence Seaway,
Any chance that you know of campgrounds near Montreal?
Cheers,Kerry Kraft.