On June 26, 1959, Canada and the United States celebrated the opening of the St. Lawrence Seaway by issuing commemorative stamps with a common design.

Fleetwood first day cover franked with Canadian and American St. Lawrence Seaway commemoratives
with Massena, New York cancellation with cachet showing an aerial view of Massena's Eisenhower Lock.

Artmaster first day cover franked with Canadian and American St. Lawrence Seaway commemoratives
with Massena, New York cancellation with cachet showing a ship in a seaway lock.

Artmaster first day cover franked with a plate block of the American St. Lawrence Seaway
commemorative with Massena, New York cancellation with cachet showing a ship in a seaway lock.

First day cover franked with a single Canadian St. Lawrence Seaway commemorative with
a Cornwall, Ontario cancellation with a handstamp cachet showing a ship on the river
approaching a lock by-passing a dam with overhead powerlines coming from the dam.

Rosecraft first day cover franked with a single Canadian St. Lawrence Seaway commemorative
with a Fort William, Ontario cancellation with a cachet showing a modern seaway lock gate.
Fort William (now part of Thunderbay) is Canada's western terminal of the seaway system.

H&E (Earl Graziadei and Harold Crick) first day cover franked with a single Canadian St. Lawrence Seaway commemorative
with an Ottawa, Ontario cancellation with a cachet showing chain links connecting symbols of Canada and the United States.

First day cover franked with a single Canadian St. Lawrence Seaway commemorative
with an Ottawa, Ontario cancellation with a cachet showing a line of ships on
the St. Lawrence River approaching the seven locks between Montreal and Lake Ontario.