The Marathon Along the Rideau Canal: Flat for 40 km, Then Parliament Hill Is Waiting

Two loops along the canal

The marathon runs in two loops parallel to the Rideau Canal, through downtown Ottawa, finishing at Major's Hill Park next to the Fairmont Chateau Laurier. The course is billed as flat, roughly 165 m of total gain, and for the most part it really is. Crowd support is good and volunteers are plentiful: on a full, that matters.

Flat, but not at the end

The detail many discover too late: the last 2 km or so of each loop climb, along the canal and behind the Chateau Laurier. And about 2 km from the finish there's a 13% kicker on the back side of Parliament Hill. You hit it twice, because the course is two loops. On the first pass you've got legs; on the second you've got 40 km in them, plus heat and humidity on your back.

Make this decision before the race, not during it: do you walk the kicker on the first loop to save energy, or run it easy? Several 2025 race reports describe athletes in serious trouble in the final stretch. Walking 200 meters at 13% costs a few seconds; blowing up there costs minutes and your finish-line photo.

The humid heat is the real opponent

Early August in Ottawa means typical highs of 26-28 °C with 70-80% humidity. In 2025 it was a hot day, with haze and an air quality alert from wildfire smoke. Reports describe athletes using ice down the tri suit, water over the head, electrolytes and cola to get to the line, and some dealing with dizziness or collapses.

Your protocol needs to be built beforehand, not improvised:

• Ice at every aid station: in the tri suit, in the cap, in your hands.
• Water over your head and neck, systematically.
• Electrolytes on a schedule, not by feel.
• If your body sends signals (chills, goosebumps, confusion), slow down immediately. Better to lose 10 minutes slowing early than to stop later.

Test all of this in training during hot weeks, including running off the bike in the heat.

Practical pacing

Our ballpark estimates for the marathon: 5:15 for the relaxed finisher, 4:30 for the mid-pack target, 3:50 for fast runners, 3:15 for top age-groupers. These are our estimates, not official data.

The classic risk on this course: the flat, crowd-lined first 20 km tempt you into running your "dream" pace. With 70-80% humidity, the bill comes due between km 28 and 35, even before the final kicker. Set your first loop deliberately conservative: if you feel good at km 30, you have plenty of time to push, and Parliament Hill will be far less scary.

What to decide beforehand

• Kicker strategy: run or walk? Decide now, for both loops.
• Written heat protocol: what you take at every aid station, in what order.
• Pacing plan B: one target for a "normal day" and one for a "feels-like 30 °C or bad air" day. In 2025, those who adjusted their expectations finished; check the air quality index in the days before and pick the right plan that morning.
• Shoes and socks tested wet: with water over your head at every aid station, your feet will be soaked for hours.

The finish at Major's Hill Park, with the Chateau Laurier in the background, is one of the most scenic finales you'll find at a North American full. Get there with something left in your legs: the 13% kicker is the final exam, and you pass it with the discipline of the first 30 km.