Eastern Ontario, broadly the region between Ottawa and Kingston, south of the Canadian Shield and north of the St. Lawrence, is one of the most historically dense regions in the province. European settlement started in the 1780s with the United Empire Loyalists. By the 1830s, the Rideau Canal was operational, and mill towns were appearing at every waterfall. By mid-century, the region had textile factories, foundries, distilleries, and implement works exporting products internationally. The ruins and remnants of that industrial past are everywhere, and the region also holds Ontario's most unusual ghost towns — the communities deliberately drowned by the St. Lawrence Seaway.
The Rideau Corridor
The Rideau Canal, completed in 1832 as a military route between Kingston and Ottawa, became an economic artery. Towns at every lock station and waterfall developed industries. Smiths Falls, with the Frost and Wood agricultural implement factory (800+ workers at peak) and the Rideau River's falls providing water power, became a manufacturing centre. Perth, on the Tay River, had distilleries and woollen mills. Merrickville had foundries and mills. Westport served the lake trade.
Today, these towns have substantial collections of nineteenth-century industrial and commercial buildings, many of them built from local limestone that has proven almost indestructible. Perth and Merrickville have done well with heritage tourism and adaptive reuse. Smiths Falls has struggled more, particularly after the Hershey chocolate factory closed in 2008 — 45 years of operation, hundreds of jobs, gone. The former industrial sites article covers specific locations in detail.
The Lost Villages
Eastern Ontario's most dramatic historical event was the St. Lawrence Seaway construction in the 1950s. The flooding of the river valley between Cornwall and Morrisburg deliberately destroyed six communities: Aultsville, Farran's Point, Dickinson's Landing, Wales, Moulinette, and Mille Roches. These were not failing settlements. Some had been continuously inhabited for 170 years since the Loyalist settlement.
On July 1, 1958, the cofferdams were blown and the water rose. Movable buildings were relocated to the new planned communities of Long Sault and Ingleside. Everything else was demolished or submerged. The Lost Villages Museum near Long Sault preserves relocated buildings and artifacts. At low water levels, submerged foundations are occasionally visible. The ghost towns near Ottawa article covers the Lost Villages in more detail.
Eastern Ontario's mix of farmland, forest, and water created a landscape dotted with historic villages and industrial sites.
The Mississippi River Industrial Corridor
The Mississippi River (not the American one — Ontario has its own) powered mills from Mazinaw Lake to the Ottawa River. Almonte, on its banks, had enough textile mills to earn the nickname "Manchester of Canada." The Rosamond Woollen Company, the most prominent operation, ran from 1857 to 1985. Carleton Place had the Findlay foundry. Lanark had woollen mills. The industrial remnants along this corridor are accessible from county roads, and a driving tour of Almonte, Appleton, Carleton Place, and Lanark can be done in a day.
Cornwall
Cornwall's cotton textile industry developed in the late 1800s, driven by St. Lawrence rapids power. Multiple mills employed thousands. The Domtar fine papers mill operated until 2006. The industrial waterfront has been partially redeveloped, but empty factories and the old canal infrastructure remain visible. Cornwall's story connects directly to the Lost Villages — the Seaway that drowned nearby communities also reshaped the city.
The Shield Edge
The northern boundary of Eastern Ontario, where limestone gives way to Canadian Shield granite, has a different character. This is where the colonization roads pushed north and the farms failed. Towns like Calabogie, Denbigh, and Plevna sit on or near this geological boundary. The back roads around them pass through country that was once more densely settled than it is today.
The K&P Railway once connected these Shield-edge communities to Kingston. When the railway was abandoned in stages through the 1980s, these communities lost their connection to markets. Foundation walls, abandoned school sites, and overgrown cemeteries mark vanished settlements. The K&P Trail now follows much of the former route, providing access to the rock cuts and bridge abutments that are the railway's most dramatic remnants.
The Ottawa Valley begins where Eastern Ontario's Shield edge meets the lumber country to the northwest. The two regions overlap and complement each other, and a thorough exploration of abandoned Ontario should cover both.