In September of 1805, the Lewis & Clark Corps of Discovery struggled to find a trail through the Bitterroot Mountains. Their travails gave name to Lost Trail Pass, crossing the Idaho/Montana border. Two peaked bands represent the Columbia River Basin drainages divided by Lost Trail: Bitterroot Clark- Fork to the north, and Salmon to the south. The middle band represents the Lost Trail National Wildlife Refuge, which provides crucial winter habitat to fish, fowl, and mammals large and small. Unnapped.