The classic Chateauguay Valley (Haut-St-Laurent) road ride
The Chateauguay Valley southwest of Montreal (aka Haut St-Laurent) has very nice roads for biking. I think the classic ride is this one.
I encourage you to stop and have a scenic break at every bridge across the Chateauguay river.
The ride is triangle shaped. It starts in Ormstown then follows the chateauguay river all the way to the US border. Then it goes straight east along the US border. Then it returns to the chateauguay river on the road LaPresse called the best bike road in Quebec.
First stop is the hamlet of Dewittville (scenic bridge) to Huntingdon (2 scenic bridges) and then the road & river turn south towards USA you'll see mountains in New York State south of Malone.
The map says cross Gilmore bridge. This is a closed-to-cars-bridge and is a great rest stop. Crossing this bridge takes you into the rural municipality of Elgin. The bakery is only open friday until 6 pm/Saturday until 3 pm. (Shortcut: Note that you could go direct to Powerscourt from Gilmore bridge on the road you were on from Huntingdon)
The covered bridge across the Chateauguay river at Powerscourt is Quebec's oldest covered bridge. Nuff said!
You will have noticed that the ride up until to this point (from Ormstown to Powerscourt) was very good bike riding. I would like to make it known that for me, from this point it is bike paradise.
From Powerscourt you go straight east on First Concession road, then you turn left and have a lovely descent (zoomy, then mellow) back to the Chateauguay river through apple orchards, maple forests, and farm/forest mix. (Shortcut: turn north on Montée Rockburn from the First Concession. However the map version is only a couple miles longer, and adds a heck of lot of good riding into this little corner of the ride.)
You will eventually arrive at Dewittville, turn right and head back for the final leg of the ride to Ormstown along the Chateauguay river. Try to spot the century-old giant cottonwood trees. They are tall!
Tips: a good regional map, washrooms, full retail services and parking are all available at the IGA mall in Ormstown at corner of Routes 138 & 201. There is a hospital in Ormstown with an emergency room. To get to Ormstown take pont mercier/Rt 138 or B) take Autoroute 30 to Rt 138 at Chateauguay, then drive west to Ormstown. You can also come via Valleyfield. (You cannot cross bridges from valleyfield south to Ormstown on bike.)