Newmarket, town, seat of York Regional Municipality, in southern Ontario, Canada. Located on the Holland River, it is a regional center and a suburb of Toronto. Major manufactures are rubber and plastic products, motor-vehicle parts, electrical equipment, processed food, and furniture. Agricultural output includes dairy products. Newmarket is the location of Pickering College, a foundation run by Quakers. A point of interest is the Elman W. Campbell Museum, which contains displays about the town's history.
The site was settled by Quakers in 1801 and incorporated in 1880. Newmarket's name is believed to have come from its role as a new market for commerce in the early 19th century. It experienced several periods of growth in the 20th century.
