The Fossil Gap Trail begins near the halfway point of the Fossil Creek Trail
. The trail crosses open meadows for a short distance to Fossil Creek. This is the trail junction with the Caribou Bluff Cabin Connector
From here, the route follows Fossil Creek downstream for a bit until it climbs up and off of the creek, heading back into the woods. From this point, the trail parallels Fossil Creek through the Gap and then across open meadows toward Beaver Creek. Carefully cross Beaver Creek and then continue along the creek, across a slough, and into the trees again.
The far end of the trail continues through black spruce forest before crossing a bridge at Montana Creek. From there, the route travels through open meadows marked with tripods to its junction with the Colorado Creek Trail