Canadian federal elections have provided the following results in the suburban sections of Durham and York Regions.
Regional profile
The region is within the 905 Area Code (often referred to as the "905 belt"), and is populated predominantly by middle class, suburban voters. After leaning Liberal from 1968 to 1974, the area tilted conservative in the late 1970s and 1980s, when it only had three seats, helping the PCs win two majority governments in the 1980s. Support for the Co-operative Commonwealth Federation and the New Democratic Party, however, was heavy in the unionist city of Oshawa, especially when popular NDP leader Ed Broadbent held that seat from the late 1960s to late 1980s.
However, rapid growth of the Greater Toronto Area accompanied with an influx of immigrants and urban professionals turned the region into a Liberal stronghold, similar to the outer areas of the City of Toronto and the Mississauga-Brampton-Oakville area to the west of Toronto. By 2000, the Liberals swept all seven of its seats and its provincial rejection of the Tories in 2003 helped to secure Dalton McGuinty's provincial liberal landslide majority.
In 2006, the Liberals easily held onto most of the seats, with the exception of Oshawa and Whitby—Oshawa, which were taken by the Conservatives. In 2008, the Conservatives gained another two seats, Thornhill and Oak Ridges—Markham, and in a 2010 by-election the riding of Vaughan. In 2011, the Conservatives took another 3 seats (Ajax-Pickering, Pickering-Scarborough East and Richmond Hill); leaving the Liberals with one seat of nine in the area - Markham—Unionville. In 2015, however, the meltdown of Tory support in southern Ontario saw the Liberals seize all but three of the region's 12 seats, those being Oshawa, Thornhill, and surprising, Markham-Unionville.