The Tamarack Ottawa Race Weekend is Canada’s largest running festival held annually in May in Ottawa, Ontario. Established in 1975, it features multiple races attracting both elite athletes and recreational runners from around the world, including the Boston Marathon qualifying Tartan Ottawa International Marathon.

Participants enjoy scenic courses passing landmarks such as Parliament Hill and the Rideau Canal, with comprehensive on-course support including periodic water, nutrition, and misting stations, medical services, and lively cheer zones. The Green Bib option offers runners a chance to fundraise for the Desjardins Charity Challenge instead of receiving a medal.

\* Road surface throughout \* Boston Marathon qualifying marathon \* Elite Label Road Race designation by World Athletics \* Support stations with water, nutrition, and medical aid \* Misting and cooling stations along the route \* Portable toilets at every aid station \* Courses feature iconic Ottawa landmarks

- Scenic routes passing Parliament Hill and the Rideau Canal
- Kilometer markers throughout the course
- Water and Xact Nutrition stations approximately every 3 km
- Cooling and misting stations available
- Portable toilets at every water station
- Cheering and entertainment stations
- Full medical services on route and at finish line
- Green Bib option supports the Desjardins Charity Challenge
- Stroller allowed only in the Ottawa 2K event