Markham – Thornhill is one of the largest ridings in the City of Markham and York Region with a population over 100,000 within an area of 42 km². The electoral district is bordered by Bayview Avenue to the west, Steeles Avenue to the South, Highway 407 to the north and the Rouge River to the east.

Markham is the most ethnically diverse municipality in Canada, and the Markham – Thornhill area reflects this diversity in ethnicity and in its the local neighbourhoods. Markham-Thornhill is a combination of rich heritage in Thornhill upscale urban neighbourhoods to the east, a vibrant commercial areas on Yonge Street and Bayview Avenue, world class hiking trails, the scenic Rouge River Valley and fine Asian and South Asian Cuisines throughout. A quality community to live, work and play.