Heintzman House

The Heintzman House (c. 1817), also known as Sunnyside Manor Farm, is one of the oldest buildings in Thornhill-Markham, Ontario, where it sits on the crest of Bay Thorn Drive.

The Yonge Street Crown Grant property (Lot 32, Concession 1, Markham) was awarded to United Empire Loyalist Anthony Hollingshead in July 1798.

Charles was born in Toronto and educated at St. Andrews College; after graduation he served his apprenticeship in the family's piano manufacturing business.

Charles was a keen outdoors man, and both of the Heintzmans were interested in farming and kept a herd of prized Jersey cattle on their Thornhill property.

Mr. and Mrs. Heintzman added the pillars and portico as well as the conservatory; a garage and servant's quarters, taking care that these and other alterations (mix of Georgian and Regency[3]) would preserve the character and unique features of the house.

Residents in the area, led by Alan Sumner, opposed the plan and launched a campaign to save Sunnyside Manor and were successful in convincing the then Town of Markham to purchase the property in 1966.

The Heintzman House is today a venue for weddings, parties, receptions and other special events, and is used by local organizations, for business meetings, and in commercial and film work.