The highway's present alignment measures 319 kilometres (198 mi) long, of which the western 180 km (110 mi) between the inter-provincial border with New Brunswick at Fort Lawrence through to Sutherlands River is a 4-lane divided freeway. The eastern 142 kilometres (88 mi) from Sutherlands River to River Tillard is a mixture of 2-lane controlled access freeway known as a Super 2, uncontrolled access 2-lane highway, and 4-lane divided freeway sections.

Highway 104 is divided into two distinct sections; the Trans-Canada Highway section which runs from the New Brunswick border to Port Hastings, and a smaller section on Cape Breton Island between Port Hawkesbury and St. Peter's.^[2]

Trans Canada Highway edit

From the inter-provincial border at Fort Lawrence, Highway 104 is a 4-lane divided freeway with posted speed limit of 110 kilometres per hour (70 mph) and runs east for 48 kilometres (30 mi) past the towns of Amherst and Oxford to Thomson Station. This section had been built in the 1960s as a Super 2 and was upgraded to a 4-lane divided freeway that opened in 1993. From Thomson Station the highway runs southeast for 45 kilometres (28 mi) to Masstown, this segment is a tolled section known as the Cobequid Pass, which opened on 15 November 1997. From Masstown, the highway runs east and northeast for 14 kilometres (9 mi) to the rural community of Onslow, near Truro, and intersects Highway 102, the main 4-lane divided freeway connecting the Trans-Canada Highway with Halifax and southern Nova Scotia.

Highway 104 continues for 55 kilometres (34 mi), past Westville, to Highway 106, a branch of the Trans-Canada Highway that connects to Prince Edward Island via ferry. The highway continues east for 4 kilometres (2 mi) to Stellarton and New Glasgow, with the highway passing through Stellarton; however, New Glasgow is located just to the north of the highway. The highway continues to Sutherlands River, where it reaches the eastern extent of the end of the 4-lane divided freeway.^[2]

East of Sutherlands River, Highway 104 becomes a Super 2 with a posted speed limit of 100 kilometres per hour (60 mph). The highway runs east for 17 kilometres (11 mi) to Barney's River Station, and was built between 1964 and 1965 as a Super 2 and remains as a controlled access highway with dedicated passing lanes.^[4] East of Barney's River Station, the highway runs east for 10 kilometres (6 mi) to James River as a 4-lane divided freeway, which opened to traffic on May 18, 2023.^[5] This segment bypasses a 12-kilometre-long (7.5 mi) 2-lane uncontrolled access highway segment, which was formerly part of and is now once again part of Trunk 4.^[4] Past James River, the highway continues east for 12 kilometres (7 mi) to Addington Forks as a 4-lane divided freeway^[4] where the highway runs east for 11 kilometres (7 mi) to South River Road, along a new alignment of 4-lane divided freeway that opened on September 19, 2012. Prior to this new alignment opening, Highway 104 ran east on the present alignment of Trunk 4 and Post Road in the town of Antigonish and included three intersections controlled by traffic lights. The highway continues from South River Road as a 4-lane divided freeway, which opened October 22, 2016, for 7 kilometres (4 mi) to Dagger Woods.^[6] Prior to this new alignment opening, this section was an uncontrolled access highway (formerly Trunk 4).^[2]

From the end of the freeway section at Dagger Woods, the highway runs east for 4 kilometres (2.5 mi) to Pomquet Forks as a Super 2 and remains as a controlled access highway, although there are several at-grade intersections. East of Pomquet Forks, the highway runs east for 3 kilometres (2 mi) to Heatherton as an uncontrolled access highway (formerly Trunk 4) and speed limit reduces 90 kilometres per hour (55 mph). Past Heatherton, the highway runs east for 29 kilometres (18 mi) to Auld's Cove and speed limit increased back to 100 kilometres per hour (62 mph). At Auld's Cove, the highway becomes an uncontrolled access highway with a posted speed limit of 70 kilometres per hour (45 mph) and begins a concurrency with Trunk 4. It crosses the Strait of Canso along the 1.4-kilometre-long (0.9 mi) Canso Causeway to Port Hastings on Cape Breton Island. At Port Hastings, the highway intersects Trunk 4, Trunk 19 and Highway 105 at a roundabout where Highway 105 proceeds east carrying the Trans-Canada Highway designation.^[2]

Cape Breton Island edit

From the roundabout at Port Hastings, there is an 8-kilometre (5 mi) gap in Highway 104 which is connected by Trunk 4, passing the town of Port Hawkesbury. The highway reappears at the Exit 43 interchange for Trunk 4 in Melville, just outside of Port Hawkesbury.^[2] A Highway 104 bypass from Port Hastings to Melville has been proposed in the past. Concept designs have shown a new alignment of 4-lane freeway being built around the northwest side of Port Hastings, crossing Highway 105 at a new interchange near an electrical substation. The new alignment of Highway 104 would proceed east and then southeast approximately following a power line corridor to the Exit 43 interchange in Melville.

From Port Hawkesbury, the highway runs east as a controlled access Super 2 for 34 kilometres (21 mi) to its current eastern terminus at an at-grade intersection with Trunk 4 in River Tillard, near St. Peters. An extension of Highway 104 from River Tillard to Sydney River has been proposed in the past. The Nova Scotia provincial government has designated the entire length of Highway 104 from Fort Lawrence to River Tillard as a "strategic highway" to qualify for federal cost-sharing of maintenance and future upgrades. This designation has also been applied to the remaining Trunk 4 corridor in Cape Breton along the south shore of Bras d'Or Lake from St. Peters to Sydney River. It is eventually envisioned that the Trans-Canada Highway will follow the entire length of Highway 104 from Amherst to Sydney River as a 4-lane freeway, upgraded from the existing two-lane freeway and uncontrolled access sections of the highway.^[2]

Highway 104 was upgraded in various stages as follows:

• KM 0 to 49, section from the New Brunswick border to Thomson Station had been built in the 1960s as a Super 2 and was upgraded to a 4-lane divided freeway in 1993.
• KM 49 to 92, section from Thomson Station to Masstown had been built as a 4-lane divided freeway that opened November 15, 1997; tolled section known as Cobequid Pass.
• KM 92 to 146, section from Masstown to Salt Springs had been built in the 1960s as a Super 2 and was upgraded to a 4-lane divided freeway that opened in the early 1990s.
• KM 146 to 159, section from Salt Springs to Westville Road was built as a new alignment of 4-lane divided freeway that opened in the late 1990s. Prior to this new alignment opening, Highway 104 ran east on the present alignment of Trunk 4.
• KM 159 to 166, section from Westville Road to Plymouth had been built in the 1960s as a Super 2 and was upgraded to a 4-lane divided freeway that opened in the early 1990s.
• KM 166 to 174, section from Plymouth to Pine Tree had been built in the 1960s as a Super 2 and was upgraded to a 4-lane divided freeway that opened in fall 2011.
• KM 174 to 177, section from Pine Tree to Sutherlands River had been built in the 1960s as an uncontrolled access highway (formerly Trunk 4) and was upgraded to a 4-lane divided freeway that opened in fall 2012.
• KM 177 to 219, section from Sutherlands River to Addington Forks had been built in the 1960s as a Super 2. It was upgraded to a 4-lane divided freeway by July 25, 2023.
  • KM 198 to 219, section from Barney's River Station to James River, built in the 2020s as a 4-lane divided freeway that opened May 18, 2023.
• KM 219 to 228, section from Addington Forks to South River Road, built in the 2010s as a 4-lane divided freeway that opened September 19, 2012.
• KM 228 to 235, section from South River Road to Dagger Woods, built in the 2010s as a 4-lane divided freeway that opened October 22, 2016.
• KM 235 to 236, section from Dagger Woods to Pomquet Forks had been built in the 1960s as a Super 2.
• KM 236 to 239, section from Pomquet Forks to Heatherton had been built in the 1950s; originally part of Trunk 4.
  • KM 235 to 242 will be the next section to be twinned, with construction to begin sometime in 2024-2025.
• KM 239 to 269, section from Heatherton to Aulds Cove had been built from 1965-1969 as a Super 2.
• KM 269 to 274, section from Auld's Cove to Port Hastings had been built and upgraded in the 1950s and 1960s, with the Canso Causeway opening in 1955.
• KM 282 to 319, section from Port Hawkesbury to River Tillard has been built in the 1970s as a Super 2.

The Province of Nova Scotia awarded the P3 contract that will twin a 38-kilometre (24 mi) section of Highway 104 between Sutherlands River and Antigonish to Dexter Nova Alliance.^[7] As part the project, there will be 28 kilometres (17 mi) of existing highway upgraded and a 10-kilometre (6 mi) new, realigned section; the bypassed section of Highway 104 between Barney's River Station and Marshy Hope would revert to being part of Trunk 4.^[8][9] Construction began in the spring of 2020, with a completion date of no later than the end of 2023.^[7]

The province of Nova Scotia has proposed construction of a new 84-kilometre (52 mi) 2 lane arterial from the current end of Highway 104 at St. Peter's to Highway 125 at Sydney.^[10] This highway would travel mostly east of the current Trunk 4 and open as a Super 2. It would serve as a bypass of Trunk 4 and likely take designation of the Trans Canada Highway rather than Highway 105. When completed, this would provide nearly continuous controlled access highway across Nova Scotia on the Trans Canada Highway. Construction costs are estimated to be approximately $500 million and tolls have been proposed in the past. This project is currently not on the province's 5-year highway plan.^[11]