The Ottawa Self-Transcendence 24 Hour Race is an Ultramarathon race in Ottawa, Canada. The run takes place annually in September, organised by the Sri Chinmoy Marathon Team. It is held inside the Louis Riel domeCoordinates: 45°26′32″N 75°34′20″W / 45.442100°N 75.572199°W, on a 400-metre track. Runners from Canada and all over the world participate. It is the longest-running 24 hour race and oldest timed ultrarace worldwide.
The race first took place in 1981. Since its debut, it has hosted the National 24 Hour Championship on several occasions. Since 2009, it has also included a 6-hour, a 12-hour and a 6-hour relay race.
In May 1981, Al Howie set the Canadian and North American record. The men's course record is 242.919 km by Peter Holubar in 1990, and the women's is 214.487 km by Jamie Donaldson in 2009. In 2013, Jon Olsen ran 100 miles in 11:59.28, setting a new American 100-mile track record and a new North American record.