Maps: Waterloo USGS Quad and Beaverhead-Deerlodge National Forest Map.

Finding the trailhead: From Exit 256 in Cardwell (east of Butte on Interstate 90), drive south on Highway 359 for 5 miles. Then turn right, heading south on South Boulder Road (Forest Road 107). The pavement ends after 2.7 miles. Stay on the main road (FR 107) through the small community of Mammoth for 14.5 miles. Stay right when the road forks, continuing on FR 107. After almost 17 miles of dirt road driving (high-clearance vehicle recommended), you reach the Bismark Reservoir and the trailhead for both Louise Lake and Lost Cabin Lake. You can still follow the original route to Louise Lake, leaving FR 107 a mile before Bismark Reservoir, but a new, more gently graded trail now departs directly from the reservoir.

Parking & trailhead facilities: Ample parking.

The hike: The Tobacco Roots offer many short hikes, such as the one to Louise Lake, that are suitable for families. However, wait until mid-July for the snow to melt.
From Lost Cabin/Louise Lake Trailhead, Trail 168 climbs gradual switchbacks for 3.5 long miles to the lake. The trail climbs steadily but with no brutal pitches. Carry your drinking water, as there are only a few water holes along the way.

Louise Lake sits in a cirque with massive, 10,353-foot Middle Mountain to the south. The lake has a small population of large cutthroat trout that can be very fussy about which fly they take. If you find the fly that works, only catch enough for supper, leaving the rest for the next angler. Climbers in your party will be tempted to scramble up Middle Mountain, a nontechnical climb.

The Forest Service has recognized this fine trail as a National Recreation Trail for its outstanding scenery and exceptional recreational opportunities. It is closed year-round to all motorized vehicles.