Highway 104 in Nova Scotia, Canada, runs from Fort Lawrence at the New Brunswick border near Amherst to River Tillard near St. Peter's. Except for the portion on Cape Breton Island between Port Hawkesbury and St. Peter's, it forms the main route of the Trans-Canada Highway across the province. Highway 104 mostly supplants the former route of Trunk 4. In 1970, all sections of Trunk 4 west of New Glasgow were renumbered, although the number was added back in the Mount Thom and Wentworth Valley areas in the 1990s when new alignments of Highway 104 opened to traffic.