Ontario's highway system has been rebuilt and rerouted so many times that abandoned road alignments are everywhere. When a curve was straightened, a bypass built, or a highway widened, the old route was often simply left in place — a strip of cracked asphalt leading nowhere, reverting to forest on both sides. These old alignments are oddly compelling to explore: they show you where the road used to go, and by extension, how people used to travel through the province.
Highway 17 Old Alignments
Highway 17, the Trans-Canada route through northern Ontario, has been realigned so many times that dozens of old sections exist along its length. The most interesting are in the Ottawa Valley between Arnprior and Mattawa, where the original highway followed the Ottawa River more closely than the current route.
Near Deep River, the old Highway 17 alignment ran through the town itself, while the current route bypasses it. The old alignment is now a local road, but the change in character — from Trans-Canada highway to quiet town street — is visible in the road width, sight lines, and engineering. Near Deux Rivières and Bissett Creek, abandoned curves and bypassed sections of the original highway sit in the forest, accessible on foot from pull-offs on the current road.
Between Sudbury and Sault Ste. Marie, Highway 17 has been realigned repeatedly to improve safety on what is one of the most dangerous stretches of road in Ontario. Old alignments near Serpent River, Spragge, and Batchawana Bay are findable with a good map and some patience.
The Ferguson Highway
Before Highway 11 was built as a proper divided highway, the route from Toronto to North Bay followed the Ferguson Highway, named after Premier Howard Ferguson who championed northern road development in the 1920s. The Ferguson Highway was a two-lane road that ran through every small town between Barrie and North Bay. When the 400-series extension and Highway 11 improvements bypassed these towns, main streets that had been provincial highways became quiet local roads. Sundridge, South River, and Burks Falls all have main streets that were once the primary north-south highway through Ontario.
Opeongo Colonization Road
The Opeongo Road, built starting in 1852, was a government colonization road designed to open the interior of the Ottawa Valley for settlement. It ran from Farrell's Landing on the Madawaska River west through Dacre, Brudenell, and Killaloe to Opeongo Lake on the edge of Algonquin Park. The road brought settlers into land that was, in hindsight, unsuitable for farming — thin soil over Canadian Shield, short growing seasons, and isolation.
Parts of the Opeongo Road are still in use as county roads. Other sections have been abandoned and reverted to rough tracks through the bush. The original road allowance is wider than you would expect — the government specifications called for a 66-foot right-of-way — and this width is still visible even where the road surface has disappeared.
How to Find Old Alignments
The best tool for finding old highway alignments is a combination of current maps and historical air photos. The Ontario government's historical air photo archive is available online and shows highway routes from the 1950s and 1960s. Comparing these to current satellite imagery reveals where roads have moved. On the ground, old alignments are identifiable by: degraded asphalt in the forest, guard rail posts with no guard rail, bridge abutments at stream crossings with no bridge, and the unnaturally flat, wide grade of an engineered road surface.
Many old alignments are on Crown land or abandoned road allowances and are legally walkable. Some have been incorporated into snowmobile or ATV trail networks. Others are genuinely abandoned and overgrown. The website Ontario Highway History (ontariohighways.com) is an excellent resource for specific alignment details.