Rotary Park on Lake Ontario, Ajax

Highway 401

In the early 1900s, the main raoad between Toronto and Montreal was the Kingston Road (so it was called in Toronto).  Highway 2 connected all the towns along the Lake Ontario shoreline, and then all the towns further east along the St Lawrence River.  Heading west from Toronto, Highway 2 connected major towns to Windsor, Ontario, though Highway 3 was the major road along the north shore of Lake Erie from Fort Erie (across the Niagara River from Buffalo) to Windsor. These roads were the carriage and postal routes since the early 1800s.

In 1917, the first concrete expressway, 2-lane Lakeshore Road, which went for 64 kilometres between Toronto and Hamilton was built. This was the predecessor of today’s Queen Elizabeth Way (QEW). In 1931 this was doubled in size, with two lanes in each direction. The upgraded QEW opened in summer of 1940, and pioneered efficient highway design and mechanized highway construction techiques.  In 1935, the Ontario government started improving Highway 2 (Kingston Road) in Scarborough, including a long bridge over Highland Creek, which straightened the route, and began work to extend this to Oshawa, though completion was interrupted by wartime re-prioritization of government effort.  The road to Oshawa was completed after the war, in 1947, then called Highway 2A.

In the 1930s, congestion started to become a problem in towns and cities along Highway 2 which was a standard two-lane highway. In 1939, the Ontario government expressed plans for a trans-provincial expressway running from Windsor all the way east to the Ontario-Quebec border.  Along the St Lawrence River,  Highway 2S (S for Scenic) was built   to connect Kingston and the other towns to the new Ivy Lea Thousand Islands Bridge, though it was only a gravel road when it opened in 1941. In 1952, the route number was changed from Highway 2A to Highway 401 reflecting its 4 lane divided highway status. The concept was to build a new highway route away from  Toronto, as a bypass of the crowded city roads and existing highways.
Frenchmans Bay, i nPickering
The Toronto Bypass was begun in 1951,  and was completed in 1956. It ran from Highway 27 (which was concurrently widened to a full expressway from the Toronto Bypass to the Lakeshore) in Etobicoke to connect to the existing West Hill segment in Scarborough. In 1953, the Toronto to Barrie highway was completed  and was designated Highway 400, and connected to the Toronto Bypass.

Within a few years of opening the 4-lane Toronto Bypass was congested (by 1959, 85,000 cars a day were crowding a roadway designed for 48,000 daily vehicles) and  the Department of Highways made plans to widen it to 12 lanes starting in 1963.  Other high priority sections identified for improvement included sections from Windsor to Tilbury, London to Woodstock, Milton to Toronto, Oshawa to Port Hope, Trenton to Belleville, and Kingston to Gananoque, with gaps filled in over the remainder of the 1960s.

In 1954, the New York Thruway conected Buffalo to New York City, and the New York goverment  recommended that Ontario build a more direct way to connect Buffalo to Detroit than the existing 2-lane Highway 3. By 1956, construction had begun on an upgraded highway between Highway 4 in London and Highway 2 in Woodstock, as well as on a more direct route between Windsor and Tilbury. In 1958, a new highway 2 along the newly completed St Lawrence Seaway was opened to accommodate traffic displaced from a portion of Highway 2 through “The Lost Villages” of the Saint Lawrence Seaway. And a new route away from the St Lawrence, bypassing Morrisburg, was built to speed traffic between Montreal and Kingston.

By the end of 1960, the Toronto section of the highway was extended east to Port Hope, and the next year to almost Trenton (Now Quinte West), and in 1962 as far as Kingston.  By 1960, the highway was extended westwards to Milton (where the Milton Airport was, which in 1960 was renamed Toronto International, and in 1984 renamed Pearson International YYZ) and then Kitchener, and the following year as far as Woodstock. By 1963 it was completed to London, connecting to the Chatham to Windsor portion already completed.

By 1964, the highway extended continuously from Windsor right to Cornwall and the Quebec border (where it joined Autoroute 20). The last section of Highway 401 was completed between Gananoque and Brockville (the Thousand Islands Bypass) in 1968. The highway was officially named the Macdonald-Cartier Freeway in 1965, to commemorate two of Canada’s Fathers of Confederation, Sir John A. Macdonald and Sir George Etienne Cartier. One from Lower Canada (Quebec) and one from Upper Canada (Ontario). Signs along the freeway had shields with the letters “M-C”, but by 1997, these references had been removed along the highway.


Milton-Kelso-401 West-Bound Traffic - sliver ( Stefanie Richardson)

Milton-Kelso-401 West-Bound Traffic – sliver ( Stefanie Richardson)

Ajax Village shopping, on old highway 2

The Toronto Bypass was widened to a minimum of twelve lanes (six lanes per direction) from Islington Avenue to Neilson Road during the 1960s and early 1970s. With three express lanes and three collector lanes in each direction, and traffic able to switch lanes at strategic spots along the way. The complex multi-level interchanges to get traffic to-from the “local” and “express” lanes onto the Don Valley Parkway (Highway 404), Highway 400 to Barrie, and the Allen Expressway into Toronto were marvels of the time.

Belleville, overhead view

A new Highway 409 was built to move westbound traffic efficiently to Pearson International Airport, and and new Highway 410 for eastbound traffic. In 1985, another multi-lane collector-express section of Highway 401 was completed between Highway 427 and Highway 403 in Mississauga, west of the Airport, boasting eighteen though lanes (nine lanes for each direction). Later, a minimum of twelve lanes (six lanes in each direction) were built along Highway 401 between Neilson Road (Scarborough) and Brock Road (Pickering), completed in 1997. Highway 401 was widened to six lanes through Ajax, Whitby, Oshawa and Bowmanville in the 1970s and early 1980s. Since the late 1990s, Highway 401 has been widened to six lanes from the Highway 35 Interchange near Bowmanville to the Burnham Street Interchange in Cobourg, and further extended to beyond Nagle Road near Cobourg which will be completed by late 2017.Kayaking in Thousand Island National Park

In 2007, Highway 401 from CFB (Canadian Forces Base) Trenton to Toronto was dedicated as the “Highway of Heroes,” to commemorate Canada’s fallen soldiers who died serving in Afghanistan. Highway signs for the Highway of Heroes designation bearing a large red poppy were installed along Highway 401 between Toronto and Trenton at that time

Exits along Highway 401 are numbered based on their distance from the Ambassador Bridge in Windsor. Approximate distances along the highway can therefore be calculated by subtracting one exit number from another. The posted speed limit on Highway 401 is 100 km/h (60 mph) so travel times can easily be estimated based on exit number differences and therefore distances.

Kingston to Montreal 243 km

Kingston - 401 West Kingston hill sliver (Peter Munro)

Kingston – 401 West Kingston hill sliver (Peter Munro)

Montréal From Parc Jea

  • The brdiges ovedr the St Lawrence Seaway were built at the same time as the 401 was extended, to improve travel and commerce between Canada and the USA. From West to east:
    Ivy Lea Thousand Islands Bridge  (Gananoque-Orleans)  opened in 1937 with additions in 1960, crossing via Wellesley Island with a suspension bidge over the main shipping channel and a truss girder bridge over a smaller span. Connects to Interstate 81 in New York State
    Ogdensburg-Prescott International Bridge (Prescott-Ogdensburg) is a single span  suspension bridge opened in 1960
    Seaway International Bridge (Cornwall- Massena) opened in 1958. Also called the Three Nations Crossing, recognizing the Akwasasne First Nation who’s land it crosses. In 2014 the new lower level North Channel span replaced the  1962 high level bridge. These replace an earlier 1935  road and rail bridge at this location.


Highway 401 runs continuously from Windsor right to Quebec, where it joins Autoroute 20 and continues into Montreal and beyond to Quebec City and the Maritimes. Travellers and truckers can also choose the AutoRoute 30 Montreal South Bypass to avoid driving across the Island of Montreal and its congested urban highways. The highway was officially named the Macdonald-Cartier Freeway in 1965, to commemorate two of Canada’s Fathers of Confederation, Sir John A. Macdonald and Sir George Etienne Cartier. One from Lower Canada (Quebec) and one from Upper Canada (Ontario). The last section of Highway 401 was completed between Gananoque and Brockville in 1968.

2012: Montreal South Bypass (AutoRoute 30) was completed, following crossing the St Lawrence at Bauharnois and then skimming along Montreal’s South Shore communities to skip Montreal Island portion of AutoRoute 20 or AutoRoute 40. This is a toll route (modest $) with the toll plaza just south of the west junction with AutoRoute 30 / Highway 401.

2016: Improvements around Kingston, Ontario: 401 – Hwy 15 to Frontenac Cty. Rd. 38 “Phase 4” Montreal St. and CNR overheads, Kingston Bridge replacement / widening / interchange improvements

Truck Transponder Automation

Between June 1990 and 1998, Highway 401 and Interstate 75 were part of a pilot project to test the reliability and versatility of an automated tracking system for transport trucks. Termed “MACS” (Mainline Automated Clearance System), it allows a truck to travel from Florida to Ontario without a second inspection. Following the pilot project, MACS was deployed at every inspection station along I-75 from Miami to Detroit, and along Highway 401 from Windsor to Belleville in 1994. Exact time, date, location, weight and axle data are logged as a truck approached an equipped station.

Trans-Canada Highway Toronto Bypass Itinerary Map

Use mouse to drag/move map. Click on “+” or “” to zoom in or out. “Satellite” combines map & photo.