Comprising a privately leased segment and a publicly owned segment, the route spans the entire Greater Toronto Area (GTA) around the city of Toronto, travelling through the suburbs of Burlington, Oakville, Mississauga, Brampton, Vaughan, Markham, Pickering, Whitby, and Oshawa before ending in Clarington, north of Orono.

It begins at the junction of the Queen Elizabeth Way (QEW) and Highway 403 in Burlington and travels 108.0 km (67.1 mi) across the GTA to Brock Road in Pickering.

[11] The segment is operated privately under a 99-year lease agreement signed with the Conservative provincial government, which was sold in 1999 for about C$3.1 billion to a consortium of Canadian and Spanish investors operating under the name 407 International Inc.[12] The privatization of the Highway 407 ETR section has been the source of significant criticism,[13] especially regarding increases in tolls, plate denial, and false charges.

[16] Highway 407 was designed with aesthetics and environmental concerns in mind, featuring landscaped embankments, 79 storm drainage ponds, and a curb and gutter system.

At an interchange with Appleby Line (Halton Regional Road 20), the highway straightens and travels parallel to Dundas Street before passing over Bronte Creek and under the Canadian National Railway's (CN) Halwest Subdivision.

It crosses the West Humber River and former Highway 50 in Claireville Conservation Area before curving east into Vaughan, in York Region.

The Highway 427 interchange is a four-level partial stack located just north of Steeles Avenue in Vaughan and adjacent to the 407 ETR Concession Company offices.

[14][15] Still travelling alongside a power transmission corridor, Highway 407 crosses a complex rail wye which provides access to the CN freight yards to the north.

After interchanging with Keele Street (York Regional Road 6), the route gently curves northward, passing under the CN Newmarket Subdivision, which carries the GO Transit Barrie Line and crossing the Don River.

It curves back eastward as it interchanges with Dufferin Street (York Regional Road 53), travelling adjacent to and south of Highway 7.

A partial interchange with Leslie Street (York Regional Road 12) precedes the third and final large freeway–freeway junction at Highway 404.

[14][15] A new interchange has been built in conjunction with the provincially maintained and tolled extension, Highway 407E, which was constructed east of this point, and ties in with the current freeway, eliminating the at-grade intersection.

However, the province set out limitations in the 407 ETR lease contract for maintaining traffic volumes to justify toll rates.

Despite this, rates have increased annually against the requests of the provincial government, resulting in several court battles and the general public regarding the route as a luxury.

[17] As part of the contractual agreement with the government, the MTO is required to deny licence plate validation stickers to drivers who have an outstanding 407 ETR bill over 125 days past due.

[69][dubious – discuss] On October 5, 2010, the Canada Pension Plan announced that an agreement had been reached with the highway's owners to purchase a 10% stake for $894 million.

In 1986, Premier David Peterson was given a helicopter tour of the city during rush-hour; construction of the highway was announced soon thereafter, and began in 1987.

The Peterson government sought out private sector partnerships and acquired innovative electronic tolling technology.

However, due to the protest of local residents and officials concerning traffic spill-off (a scenario revisited with the extension to Oshawa[76]), the freeway was opened only as far as McCowan Road on February 18.

[78] In 2000, the 407 consortium had planned to extend the four lane highway by 16 kilometres eastward from Markham to Brock Road in Pickering by the end of the following year.

The Ontario-based corporation, known as 407 International Inc., was initially owned by the Spanish multinational Ferrovial through its subsidiary Cintra Infraestructuras (61.3%), the Montreal-based engineering firm SNC-Lavalin (22.6%), and CDP Capital (16.1%).

[16] The highway has since been described as a "value generating monster" and "cash cow" for SNC-Lavalin[38] and one of the "worst financial missteps" by any government in Ontario's history.

Extensions westward to the QEW and eastward to Highway 7 and Brock Road in Pickering were constructed by the corporation, as mandated in the lease agreement.

However, the Bob Rae led Ontario government altered these plans in 1995,[73] and the corporation constructed this section quickly upon obtaining the lease.

[5] A provincially operated 65-kilometre (40 mi) long extension to the 407 ETR, known as Highway 407 East (or 407E) during planning, began construction in 2012, with the project undertaken in two separate phases.

[88] The contract, which is valued at $1.6 billion and includes construction and operation of the highway, was eventually awarded to the same consortium that owns 407 ETR.

The first project, widening the highway to 6 lanes between York-Durham Line and Brock Road, began in Spring 2018 and was completed in August 2018.

[99]: Chapter 2 Cost-saving measures and ensuing safety concerns resulted in an independent Ontario Provincial Police investigation shortly before the opening of the freeway.

[102] An expert panel of engineers, assembled by the Professional Engineers Ontario, released a report outlining concerns regarding the decreased loop ramp radii and the lack of protective guardrails along sharp curves, in addition to the lack of a concrete median barrier to separate the two travel directions.

[102][103] The Ontario provincial government has quarrelled with 407 ETR over toll rates and customer service but is largely tied down by the lease contract.