It was the fastest growing riding in the province, having experienced a 52.5% increase in population from 2001 to 2006.

It included the town of Whitchurch–Stouffville, most of the township of King (excepting extreme northeast) the northern portions of the town of Richmond Hill (including all of Oak Ridges), and the northern and eastern portions of the city of Markham.

Communities in Oak Ridges—Markham are the destination for many immigrants to Canada, composing about 41.6% of the population, or about 70,000 of its residents.

[1] The primarily urban district has a low proportion of Aboriginal residents compared to other parts of Canada, with just 625 people identifying themselves of such descent.

[3] The riding consists of part of the Regional Municipality of York including: