[Permits required - Lake O'Hara backcountry]
Lake McArthur is a stunning lake located in the backcountry of Yoho NP. The trail to Lake McArthur is a bit over 7 km round trip with almost 400 meters of elevation gain, however it starts at the popular Lake O'Hara, which means you need to secure (very competitive) permits in advance for overnight camping in the area.