Trois-Rivières sits on the St. Lawrence between Montréal and Québec City, and it is much more than a fuel stop between the two. Founded in 1634, it is one of the oldest cities in Québec, with a small old quarter, a working-class river identity, and several museums that do not feel generic.
The city is strongest when it tells its industrial and institutional history. Forges du Saint-Maurice preserves the remains of Canada's first ironworks. Boréalis turns the old paper industry into a good museum, and the Old Prison gives the city one of Québec's more memorable guided visits.
Trois-Rivières is not as polished as Québec City, and that is part of the appeal. Come for a day if you are driving the St. Lawrence corridor; stay longer if you want an honest old river city with enough history to reward slow wandering.