Big Lost River - North Fork

About Big Lost River - North Fork

The North Fork of the Big Lost River is a 24.6-mile stretch in Custer County, Idaho. It's a tributary of the main Big Lost, originating deep in the mountains. This water runs clear and cold, with a defined channel and banks that can be steep in places, offering good structure for trout. You’ll find areas with faster riffles, deeper pools, and calmer runs. Access is mostly from shore, with some sections requiring a short walk from pull-offs along the road. The riverbed is a mix of gravel and rock, with occasional larger boulders providing hiding places for fish. This is classic mountain stream fishing where you can see your quarry before you cast. The North Fork is managed for brook trout and rainbow trout, and surveys have also confirmed the presence of cutthroat trout, including Yellowstone cutthroat, as well as mountain whitefish. Idaho Fish and Game stocks this river regularly with catchable-sized Yellowstone cutthroat trout, often in the 6-14 inch range, and occasionally fingerlings. You'll also find naturally reproducing brook trout throughout the system. Look for hatches of caddis and stoneflies, and expect terrestrials to be a factor later in the season. When fishing, try streamers like Woolly Buggers or Clouser Minnows in darker colors to imitate baitfish in the deeper pools. For dries, a Stimulator or a small Elk Hair Caddis can work well, especially during lower light periods. Nymphing with Pat’s Rubber Legs or Prince Nymphs in the faster water will also produce. Work the current seams and the edges of faster water where trout can ambush food. Be mindful of other anglers and give them space.