In the Bitterroot National Forest, the Como Lake Loop is an nice 8 mile hiking trek.
To reach the hiking 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.
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.
Overall, Lake Como National Recreation Loop Trail is the 10th most popular walking & backpacking of all 19 hiking in Montana.