Western Terminus:  North America's busiest route ends at at Highway 3, approximately 12km southeast of the Ambassador Bridge, in the city of Windsor.

Eastern Terminus:  Highway 401 ends at the Quebec border.  It connects to Quebec Highway A-20 which continues into downtown Montreal and many points easterly in Quebec.

Length:  817.9 km

Multiplexes:  4.3 km with Highway 6 south of Guelph

Freeway:  Entire Length

AADT (2002):  Highest:  409,000 between Highway 400 and Weston Road in Toronto;

                              Lowest:  15,300 between Highway 401TR (Tunnel Route) and Highway 3 near Windsor.

Road Info:  Highway 401 is very well maintained for its entire length (unsurprisingly considering it is the economic backbone of Ontario).  With any highway that is very well maintained, construction is very frequent along Highway 401, and there is virtually always construction at some point along the route at all times of the year.  Take care in construction zones, as backups are possible in any area of the province (though they are obviously more frequent in the vicinity of major centres).  Despite having a much higher design speed, the entire length of Highway 401 is posted at 100km/h.

Proper Municipality Name

Exit #

Intersecting Road

North / West Control City

South / East Control City

Windsor

Service Centres: WB & EB

Service Centres: WB & EB

Sarnia

City of London,  Population: 348 000 -  4 Interchanges

Downtown via Wellington Road North

Service Centres: WB & EB

Brantford

Service Centre: WB & EB

City of Mississauga

Population: 624 000

6 Interchanges

At Highway 409:  EB: C-D system  begins, to exit Highway 401 use Collector Lanes.  WB: C-D ends.

City of Toronto

Population: 2 462 000

Downtown via:

EB: Highway 427 South
WB: Don Valley Parkway

City Of Pickering: Population 92 000

2-EB, 3-WB Interchanges

City of Pickering

Town of Ajax:  Population 68 000 - 2 Interchanges

Ajax Business Centre via Salem Road South

Town of Whitby:  Population 110 000 - 2 Interchanges

Downtown Whitby via Brock Street North

City of Oshawa

415

Stevenson Road (Durham Road 53)

City of Oshawa

 Population 150 000

 3-EB, 4-WB Interchanges

Downtown via Simcoe Street North

City of Oshawa

417 - EB Partial Interchange

Simcoe Street (Durham Road 2)

City of Oshawa

418

Ritson Road (Durham Road 16) & Simcoe Street (Durham Road 2) -WB

City of Oshawa

419

Harmony Road (Durham Road 33) & Bloor Street (Durham Road 22)

Bowmanville

 2 Interchanges

Service Centre: WB

Service Centre: EB

Service Centres: WB & EB

Service Centre: WB

Service Centre: EB

City of Kingston,

Population: 110 000 -

6 Interchanges

Downtown via
EB: Sir John A Macdonald

WB: Highway 15

Service Centres: EB & WB

Service Centre -EB

Service Centre -WB

Service Centre - WB

Highway 401 Ends - Continues into Quebec as Autoroute 20