Although the Stanley Headwall is actually in B.C., most people access it from the Banff National Park. So I'll list it as such. Drive 20 miles north from Banff on Hwy 1 to Castle Junction. Take a left on Hwy 93 for a little over 8 miles to the Stanley Glacier trailhead, which is on the south side of the road. Follow the well-marked and heavily traveled switchbacked trail until it eventually emerges from the trees into the valley above. The Headwall will be looming above you to the right.

Allow 1.5 - 2 hours, depending on snow, how fit you are, and whether or not you are using skis or snowshoes.