Near Darby in the Bitterroot National Forest, the Como Lake Loop is an nice 8 mile mountain bike ride.
To reach the trailhead from the Darby Ranger Station, travel 4 miles north on Hwy 93. Turn west (left) on the Lake Como Road (County Road 82). Proceed 2 1/2 miles, then turn right towards campground at intersection before bridge, (paved campground areas). Continue on towards campground. Just past the fee area there are some parking lots on the left. Park in the lot closest on the campground. Bike route begins there at the trailhead or Trail 502.
Starting at the trailhead of Trail 502, ride west, following the trail above the north shore of Lake Como. After approximately 2 1/2 miles, take a left turn at the trail intersection to cross the pack bridge at the west end of the lake. You are now on Trail 580. Follow this trail around the south side of the lake. You will come out near the boat launch. You may ride the road across the top of the dam to get back to the north side of the lake. Turn left on the road that goes back to the campground, and return to the trailhead parking area. This completes the Lake Como Loop.
The north side trail is fairly level, (intermediate section) with several rock slides in the first mile. Riders may have to carry their bicycles over a few rocky spots. Don’t miss the trail that turns off to the pack bridge, (if you continue straight you will come to the wilderness boundary in approximately one mile. Bicycles are prohibited in wilderness areas.) You will have to carry your bike on the approach and departure of the bridge, it is steep and rocky. The south side trail has many wooden water bars that presents a challenging ride for the mountain biker (advanced skills may be needed). Also be aware that trail 580 may have considerable livestock use in the late summer and fall months.
Overall, Lake Como Loop is the 8th most popular mountain bike trail of all 32 mountain biking rides in Montana.