Unionville is a suburban village in Markham, Ontario, Canada. It is located 33 km northeast of downtown Toronto and 4 km east of southern Richmond Hill. Unionville is located between Woodbine Avenue as the western limit, alongside the Rouge River leading to McCowan Road as the eastern limit, Major MacKenzie Drive as the northern limit, and Highway 407 as the southern limit. Main Street, which was Kennedy Road in the mid-to-late 20th century, runs through Unionville while the new Kennedy runs 300 m to the east.
Tourism is a major part of Unionville's economy. The historic village or downtown section of Unionville is typical of a small town that developed over a century or so starting in the early 1840s (when Ira White erected his Union Mills) through the middle to late 20th century.