Unionville is a village and surrounding large area in west central Markham. The historic village or downtown section 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. Tourism is a major part of Unionville's economy. Main Street Unionville attracts thousands of visitors each year with its old-time atmosphere, and its many restaurants, pubs, and shops, as well as an art gallery and a unique library. Main Street also has a number of "century homes" dating back to the 19th century. Once surrounded by farmlands, the village is now surrounded by upscale suburban housing tracts as well as commercial areas.