Lower Big Lost River

The Big Lost River, outside of Sun Valley, offers two amazing experiences ranging from true wilderness fly fishing on freestone tributaries in the high desert to fishing the cottonwood-forest tailwater section below Mackay Reservoir. You can read more about the Upper Big Lost River Here.

The lower Big Lost River is a tailwater emitting from Mackay Reservoir. This fishery holds some great specimens of Rainbow trout. They grow large and fight hard due to the nutrient rich and very cold water coming from the bottom of the dam. Anglers will find Brook Trout in this tailwater as well. Access is somewhat limited due to private property, but there are public options up and down the river. Nymphing is the norm more often than not, and It is one of the best places to sight nymph for big trout, adding an exciting challenge for anglers. There are some excellent Midge, Crane Fly, PMD, Trico and Baetis hatches and spinner falls on the lower Lost, it’s just a matter of timing. The experienced fly angler is going to find this an exciting place to cast flies and challenge big fish. The wide variety of water types on the Big Lost allows Picabo Angler to guide absolute beginners as well as seasoned pros here.

Lower Big Lost River Gallery

USGS water flow and temperature gauge for Big Lost River: HERE

*Note: Due to the distance and dirt roads that keep the Lost River system quiet, we only offer ¾ day and full day trips to the upper Lost River area, and only full day trips to the Lower Big Lost River.