Big Lost River - Upper

About Big Lost River - Upper

The Upper Big Lost River flows through Butte and Custer Counties in Idaho, originating in the Pioneer Mountains and extending towards Copper Basin. This freestone river offers a high-quality stream fishery, characterized by outstanding scenery, particularly in its upper reaches. The river channel is often bordered by natural banks and can feature structure like boulder-strewn runs and overhanging tree limbs. Access is available, with facilities including campgrounds and ADA access points. Anglers typically fish this water by wading, so be prepared to cover ground. The Upper Big Lost River is home to a diverse trout population. You'll find healthy numbers of Brook Trout, Rainbow Trout, and Cutthroat Trout, along with Mountain Whitefish. The river is stocked with catchable and larger adult Rainbow Trout, as well as fingerling Yellowstone Cutthroat Trout, ensuring a robust population. Anglers can anticipate insect activity common to high-quality trout streams, including hatches of various caddisflies, stoneflies, and mayflies like Blue Wing Olives and Golden Stones. When fishing the Upper Big Lost, consider presenting attractor patterns and big, bushy dry flies to rising fish. Nymphing is also a highly effective technique, especially when targeting boulder-strewn runs. Swinging streamers under overhanging tree limbs can produce results, particularly for larger trout. Fish in the 8 to 20-inch range are common here. Given the remote nature of the upper river, it is crucial to carry all necessary supplies and be prepared for varied conditions. Always be aware of your surroundings.