Lake McArthur Trail

Why go

If you can snag access to Lake O’Hara, this 5-mile (≈8 km) loop is one of the most rewarding moderate hikes in the Canadian Rockies. The prize is Lake McArthur: an intensely blue, glacier-fed lake tucked beneath big walls between Mount Schaffer and Park Mountain. It’s also the deepest lake in Yoho (up to ~85 m), and a geological oddball—its water drains underground through fractures in the limestone rather than via a visible outlet. Translation: jaw-dropping color, dramatic cirque setting, and a bit of natural wonder to chew on.

Route, in short

Start near Le Relais Day Shelter (reached via the reservation-only Lake O’Hara shuttle or an 11 km walk/bike up the access road). The well-signed path heads past the Elizabeth Parker Hut and through McArthur Meadows toward Schäffer Lake. A steep, rocky headwall leads to the McArthur Highline area. Most hikers make a circuit using the signed McArthur Low Level and High Level trails—many prefer ascending via the Low Level and descending the Highline for maximum variety and views. Expect larch forests, airy traverses, open meadows, and boulder fields before the final roll down to the lakeshore. Plan 3–4 hours for the loop, plus extra time to linger at the water.

Difficulty and footing

It’s moderate overall (about 310 m/1,017 ft of gain) with a few short, steep, rocky sections. Trails are well maintained and junctions are clearly marked, but it’s alpine: expect uneven rock, stone steps, and occasional lingering snow early season. Confident hikers can add variations like the Big Larch section or the Highline/Low Level swap to tailor the day.

Scenery highlights

• McArthur Meadows bloom with wildflowers in mid–late July.
• In mid–late September, the larches on the Big Larch/Highline sections turn gold—some of the best fall color in the Rockies.
• From McArthur Pass and along the Highline you get sweeping views of the surrounding peaks and the limestone-bowl basin that holds Lake McArthur.
• Best lake color for photos is around midday when the sun is high.

Logistics and access

Access is tightly controlled: you’ll need an advance reservation for the Lake O’Hara shuttle to start at Le Relais, or commit to the 11 km road approach on foot/bike. There are basic supplies at Le Relais; there are no facilities at the lake. The nearby Elizabeth Parker Hut is by reservation only.

Best time to hike

Late June through early October. Expect lingering snow and chilly conditions early season. Wildflowers peak mid–late July; the famous larch show is mid–late September. Clear, calm midday light makes the lake color pop; the quota system keeps numbers reasonable, but sunny weekends are still popular.

Safety and wildlife

This is prime grizzly and black bear country—carry bear spray and make noise. Weather turns fast in the alpine, so pack layers and rain gear. The approach includes a steep headwall with rocky steps; take care descending. Because the lake drains underground, you’ll hike uphill leaving the shore.