Assiniboia Downs is a Canadian horse race track located in Winnipeg, Manitoba. It is operated by the Manitoba Jockey Club and is the site of the annual Manitoba Derby. The track is located on the western edge of the city, near the intersection of the Perimeter Highway and Portage Avenue. It was opened in June 1958, replacing the former Polo Park Racetrack, which was demolished to make way for Polo Park Shopping Centre. The main track is a six-and-one-half furlong oval.