Canadian Tire Motorsport Park (formerly Mosport Park and Mosport International Raceway) is a multi-trackmotorsport venue located north of Bowmanville, Ontario, Canada. The facility features a 2.459-mile (3.957 km), (length reduced through wider track re-surfacing done in 2003) 10-turn road course; a 2.9 km advance driver and race driver training facility with a quarter-mile skid pad (Driver Development Centre) and a 1.5 km kart track (Mosport Kartways). The name "Mosport" is a contraction of Motor Sport, came from the enterprise formed to build the track; it is pronounced as the two words actually sound, "Mo-Sport" (but is often incorrectly pronounced "Moss-Port").
Mosport has had a succession of owners since the original public company created to build the track. Two of those prior owners, Norm Namerow (who owned the track through his publishing company, CanTrack, until his death) and Harvey Hudes, have both been inducted into the Canadian Motorsport Hall of Fame for their contribution to the sport in Canada. In 1998, the Panoz Motor Sports Group purchased the facility, and in 1999, the newly formed American Le Mans Series visited Mosport for the first time. For 2001, the entire circuit was repaved to meet FIA specifications, and is now 42 feet (12.8 m) wide. Drivers were consulted to ensure the character of the "old" track was kept; almost all the "racing lines" have been maintained.
Mosport achieved acclaim though a series of international sports car races under the title "Canadian Grand Prix" normally reserved for Formula 1 races. Many events were wildly popular, breaking Canadian sports attendance records with each successive race. The success of these races led Mosport to be seen as a key component in the founding of the Can Am Series. The CanAm first visited the track in its inaugural season in 1966, and Mosport hosted at least one event in every year of the series' history, except 1968. In 1967, Canada's centennial year, Mosport hosted Formula One, USAC, and a 500cc Motorcycle Grand Prix. F1's Grand Prix of Canada remained at the track until 1977. Mosport has hosted a wide variety of series throughout its history. The circuit has held Formula One, USAC, World Sportscar Championship, Can-Am, Formula 5000, and many other sports car, open-wheel, and motorcycle series.
Mosport has had several fatalities, both track crew, drivers, and riders, the most recognized being German Formula One driver Manfred Winkelhock who was killed in 1985 when his Porsche 962C crashed into a concrete wall.  The most recent fatality at the track was in 2008 during the 29th annual Vintage Automobile Racing Association of Canada Racing Festival. Driver Dino Crescentini of Rochester Hills, MI - a ten-year veteran of vintage racing - lost control of his 1977 Wolf Dallara Can-Am car, which previously had been driven by Gilles Villeneuve.
Unlike many historic motorsport venues, Mosport's track layout has remained mostly unchanged from its original form.
Canadian Motorsports Ventures (CMV) which includes Orlando Corp. Chairman Carlo Fidani and Canadian road racing legend Ron Fellows, purchased the facility in June 2011.
In February 2012, a partnership between Mosport and Canadian Tire was announced. The partnership includes a renaming of the track to Canadian Tire Motorsport Park. The partnership will help to upgrade the facility, and improve the experience for spectators, participants, race teams, and corporate sponsors.
In the spring of 2000, Mosport opened the Driver Development Centre, a second 1.7 km, 12 turn training circuit designed for driver development. The new course was designed by the owners and instructors of the Bridgestone Racing Academy and was designed specifically with fewer guard rails, walls and minimum blind corners to meet the needs of their driver and mechanic training program.
Due to significant scheduling demands on the original grand prix circuit, the original academy course was reconstructed and lengthened to a full racing course in the fall of 2013. The new track features two configuration options; a 2.2 km intermediate course, a 2.9 km advanced course, as well as a skid pad, a pit lane, and a multi-storey event centre with classrooms and other facilities.
Mosport Speedway was a one-half mile oval speedway located on the northwest corner of Canadian Tire Motorsport Park. The track featured 800-foot long straightaways, 6-degree banked corners and two grandstands with seating for 8,500.
The oval was constructed in 1989 as a dirt track originally called Mosport’s Ascot North, named after the famous Ascot Park track in Gardena, California. The first event was scheduled in July 1989 and was to feature USAC Midgets and Sprint Cars and the World of Outlaws. The races were cancelled after the initial heat races caused deep ruts in the corners and dislodging stones hidden under the clay.
The NASCARCamping World Truck Series raced at Canadian Tire Motorsport Park in September 2013, marking the first time the series has raced in Canada. Chevrolet was announced as the title sponsor and the race is known as the Chevrolet Silverado 250.