Trunk 4 is part of the Canadian province of Nova Scotia's system of Trunk Highways. The route runs from Highway 104 exit 7 near Thomson Station to Glace Bay. Until the construction of the Trans-Canada Highway, Trunk 4 was a major traffic link in northern Nova Scotia and Cape Breton, and is still used on Cape Breton as an alternative to Highway 105. The highway was originally called the King's Highway, however, this name is no longer applied to the entire road. The only remaining historic section of the highway that maintains the name "King" is King's Road in Sydney. Route description (west to east) Thomson Station to Glenholme The section between the western terminus at Exit 7, Highway 104 in Thomson Station to Mahoneys Corner was originally built as Highway 104 in the 1960s. It was bypassed by the Cobequid Pass in 1997 and redesignated Trunk 4 at that time. The section between Mahoneys Corner and Glenholme was originally part of Trunk 4 until the 1960s when it was designated Highway 104. This section was also redesignated Trunk 4 in 1997 after the opening of the Cobequid Pass. Glenholme to Onslow The section between Glenholme and Onslow is co-designated with Trunk 2. Trunk 4 is discontinuous between Exit 14A, Highway 102 in the west and Pictou Road in Bible Hill in the east. Bible Hill to Barney's River Station Trunk 4 reappears in Bible Hill, following Pictou Road and the original Trunk 4 alignment east. In Kemptown, Trunk 4 follows an old alignment of Highway 104 for several kilometres. Trunk 4 continues east of Kemptown on its original alignment through Mount Thom to Salt Springs. From Salt Springs to Westville, the present alignment of Trunk 4 was used as Highway 104 from the 1960s until being bypassed in the 1990s. Now redesignated Trunk 4, the highway designation continues into Westville on Truro Road and then Westville Road. In New Glasgow it follows the original Trunk 4 route on Westville Road, Stellarton Road, George Street, Archimedes Street, Marsh Street and Merigomish Road before heading east toward Sutherlands River. At Sutherlands River, Trunk 4 follows a new alignment between School Rd and Highway 245. It then continues east to Barney's River Station. Marshy Hope to South River Station Trunk 4 is discontinuous between Barney's River Station and Marshy Hope as Highway 104 uses the old Trunk 4 alignment for this section.