Highway 105 in Nova Scotia represents the Cape Breton Island leg of the Trans-Canada Highway. It runs from the Port Hastings Rotary just east of the Canso Causeway in Port Hastings to the Marine Atlantic ferry terminal in North Sydney, representing a distance of 142 kilometres (88 mi).

The Trans-Canada Highway is a transcontinental federal–provincial highway system that travels through all ten provinces of Canada, from the Pacific Ocean on the west coast to the Atlantic Ocean on the east coast. The main route spans 7,476 km (4,645 mi) across the country, one of the longest routes of its type in the world. The highway system is recognizable by its distinctive white-on-green maple leaf route markers, although there are small variations in the markers in some provinces.