This is one of the great rides near Helena with a wilderness feel for an evening ride after work. This can be a great shuttle ride from the top of MacDonald Pass down to Tenmile Creek and out Rimini Road back to Hwy 12 if you park there. It is served by the Helena Trail Rider shuttle service on certain days during the summer so check their schedule.
The ride begins heading south on the CDT from the top of MacDonald Pass. The section is very technical for the first few miles with several challenging climbs. The technicality eases up a bit after a few miles and a steady climb leads to a large open meadow. The trail essentially disappears in the meadow but stay on the left of the tree line to find the trail sign.
The trail reappears here and begins to descend to the east towards Tenmile Creek on the Rimini Switchback Ridge Trail
. This is a fast descent that has it all: wide open sections, loose rock sections, tight switchbacks, and a final creek crossing. If you left your shuttle rig at Hwy 12, hang a left on Rimini Road for a flat 15-minute pedal to your rig.