Route 2 was once part of an interprovincial "Highway 2" running from Windsor, Ontario to Halifax, Nova Scotia. It was one of the initial routes defined in 1927, running from Quebec as a continuation of Quebec Route 2 via Edmundston, Grand Falls, Woodstock, Fredericton, Saint John and Moncton, After a short crossing of the New Brunswick Panhandle alongside the Madawaska River to Edmundston, Route 2 closely followed the Saint John River all the way to Saint John, crossing three times - from the east to the west at Grand Falls, back to the east at Perth-Andover, and back to the west at Hartland (on the Hartland Covered Bridge). The road on the east side of the river between Edmundston and Grand Falls had just been opened in about 1926; previously travelers had to pass through Maine (US 1, SR 165, and Boundary Road) on the west side. A Route 2A cut the distance between Fredericton and Saint John via a poorer-quality but more direct road, intersecting Route 2 at Oromocto and Westfield. Beyond Saint John, Route 2 went northeast via Sussex to Moncton, and then turned southeast to cross the Nova Scotia border near Aulac and continue as Nova Scotia Trunk 2. The original course through Aulac to the Nova Scotia border is now bypassed, with the old interprovincial bridge over the Missaguash River now demolished. The original route between Quebec and Sussex is now approximately the River Valley Scenic Drive.