Saint-Jean-sur-Richelieu sits south of Montreal, on the Richelieu River near the route between the St. Lawrence and Lake Champlain. It is close enough to the city to be easy, but it has its own identity: military history, canal paths, old river streets, and summer balloons.
The key historic stop is Fort Saint-Jean Museum, on a site used by Indigenous, French, British, American, and Canadian forces. The Chambly Canal gives the town a slower outdoor rhythm, with cycling and walking along the old waterway.
In August, the city becomes one of Quebec's most recognisable festival towns during the International Balloon Festival. Outside festival dates, it still works as a Montérégie day trip if you like river towns with real history.