This is a list of secondary highways in Cochrane District, most of which serve as logging roads, mine and dam access roads, or provide access to isolated and sparsely populated areas in the Cochrane District of northeastern Ontario.

Highway 578 was a short spur road in Iroquois Falls that was transferred to that municipality on January 1, 1998.

Located within Cochrane District, the highway extends from the community of Mead approximately 65 kilometres (40 mi) north to Lac-Sainte-Thérèse.

En route, it passes through the communities of Coppell and Jogues, and intersects with Highway 11 in Hearst.

The portion through the town of Hearst is not maintained by the Ministry of Transportation and separates the two halves of the highways by 9.5 km (5.9 mi).

A network of rural wilderness roads extending eastward from Jogues also connects the highway to Dubreuilville and portions of Missinaibi Provincial Park.

It travelled through the towns of Monteith, Val Gagné and Matheson, where it ended at Highway 101.

The road was re-aligned around the eastern part of Smooth Rock Falls in the mid-1990s.

It is one of the most isolated highways in North America, stretching 149.9 km (93.1 mi) from Cochrane into boreal forest to a mine at Detour Lake.

While the highway designation ends in Calstock, the roadway continues for several more kilometres through and past the Constance Lake First Nation.