From Montana I-90 exit 0, park on east side of the freeway. The trail forks left off of a dirt road just after gate. If you pass metal shed, you have gone too far on the dirt road.
Trail climbs north, across a road cut above I-90, through a rocky section, turns east, and rolls through mature timber to Mullan Pass. Nice wide trail. As of 2018, one section is getting a little bushy.