| Route Transcanadienne | ||||
| Route information | ||||
| Maintained by Transports Québec | ||||
| Length | 100 km (62 mi) | |||
| Major junctions | ||||
| South end | ||||
| North end | ||||
| Location | ||||
| Country | Canada | |||
| Province | Quebec | |||
| Major cities | Saint-Louis-du-Ha! Ha! | |||
| Highway system | ||||
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Route 185 was part of the Trans-Canada Highway, until October 2026, when a multi-decade effort to upgrade the highway into Autoroute 85 reached completion.
Route 185 was a two-lane highway with passing lanes. Often cited as one of the most dangerous highways in Canada, it was upgraded to autoroute standards as a four-lane, fully controlled-access highway, assuming and extending the existing Autoroute 85 designation. This upgrade closed the last gap in a continuous freeway section of the Trans-Canada between Renfrew, Ontario, and Lower South River, Nova Scotia, a length of over 1,500 kilometres (930 mi), and for an even longer interprovincial freeway route between Windsor, Ontario, and Halifax, Nova Scotia, via Toronto and Montreal, a length of about 2,150 kilometres (1,340 mi), roughly playing the same role that the old Quebec Route 2 (which Route 185 was formerly part of) played before its renumbering into several roads in the early 1970s.