The Tamarack Ottawa Race Weekend is Canada's largest multi-day running festival, drawing nearly 50,000 participants each year. Since its inception in 1975, the event has evolved from a small local race into a world-class running celebration, featuring six distinct races: marathon, half marathon, 10K, 5K, 2K, and a kids' marathon. The event is renowned for its vibrant atmosphere, with thousands of spectators, live music, and cheer zones energizing runners along the scenic routes.

The courses wind through the heart of Ottawa, showcasing iconic landmarks such as the Rideau Canal and Parliament Buildings. The marathon route is particularly unique, crossing into both Ontario and Quebec, offering runners a diverse and picturesque experience. The event is also notable for hosting two World Athletics Gold Label races: the Scotiabank Ottawa Marathon and the Ottawa 10K, attracting elite athletes from around the globe.

Beyond the races, the weekend features a lively health and fitness expo, live entertainment, and a festive beer garden near the starting area at Ottawa City Hall. The Tamarack Ottawa Race Weekend is a highlight of the Canadian running calendar, offering a memorable experience for runners of all ages and abilities.

All races are road courses, renowned for being flat and fast, making them ideal for personal bests and Boston Marathon qualification. The marathon and half marathon routes traverse downtown Ottawa, passing major landmarks such as the Rideau Canal, Parliament Buildings, and scenic riverfronts. The marathon course uniquely crosses into both Ontario and Quebec, providing a mix of urban and natural scenery. Elevation changes are minimal, with only gentle inclines and declines, ensuring a smooth and accessible experience for runners of all levels.

- Canada's largest multi-day running event with ~50,000 participants
- Six race distances: marathon, half marathon, 10K, 5K, 2K, and kids' marathon
- Scenic, flat, and fast courses ideal for PBs and Boston qualification
- Routes pass Ottawa landmarks: Rideau Canal, Parliament Buildings
- Marathon crosses both Ontario and Quebec
- Two World Athletics Gold Label races: marathon and 10K
- Festive atmosphere with live music, beer garden, and health expo