MacDonald Pass - Priest Pass Loop is a 18.5 mile moderately trafficked loop trail located near Helena, MT. The trail is rated as moderate and primarily used for hiking and mountain biking.
I'm going to hit this trail again, the day I did it, there was so much deadfall it was a challenge. That's just an observation. Trees fall. It's all good. And it's close enough to Helena to be a good day-hike that doesn't necessarily consume the whole day.