Mille Roches, Ontario

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Mille Roches is an underwater ghost town in the Canadian province of Ontario. It is one of Ontario's Lost Villages, which were permanently flooded by the creation of the St. Lawrence Seaway in 1958.

Families and businesses in Mille Roches were moved to the new town of Long Sault before the seaway construction commenced.

Mille Roches was the birthplace of Levi Addison Ault, born into a well-known and established family in the town, who moved to Cincinnati, Ohio as an adult and became a successful businessman and the city's commissioner of parks in the early 1900s. Ault also donated a large parcel of family-owned land on Sheek's Island, which became Ault Park.