Fly Fishing Big Hole River - Melrose to Twin Bridges

The lower Big Hole runs about 38 miles from the Melrose Bridge down to Twin Bridges, where it joins the Beaverhead to form the Jefferson. It is the longest of the river's three sections and the lowest, sitting near 4,844 feet in an arid valley of sagebrush benches and cottonwood bottoms. The character here is nothing like the canyon above Melrose: the river braids around gravel islands, strings long riffles into deep glides and slow pools, and slides along banks that shift between grass, brush, cottonwood roots, and rock. The current stays moderately fast through most of the year and only really slackens when the water gets low.

This is the brown trout end of the Big Hole. Surveys count roughly 3,000 trout per mile through this reach, and browns make up the overwhelming majority; rainbows are present but badly outnumbered, and mountain whitefish are abundant. The browns worth targeting run large, and large browns here behave the way large browns behave everywhere: they tuck under cover, eat big meals when the eating is easy, and rarely feed on top. That makes this streamer water first and everything else second. Work the banks and let the fly swim in the slower water — fish often follow a long way before they commit. Nymphs fished through the glides and riffle tailouts keep a rod bent between streamer eats, and dry-fly windows do open, especially in spring and fall, but nobody should drive here planning a dry-fly day.

The defining problem of this reach is summer dewatering. Irrigation withdrawals pull the river down through the heat of the year, temperatures climb as flows drop, and fishing quality routinely falls off in mid to late summer. Spring and fall are the reliable windows — spring for pre-runoff streamer fishing, skwalas, and the first mayflies; fall for blue-winged olives, mahoganies, and the best streamer fishing of the season as the browns turn territorial. The USGS gage near Glen, station 06026210, sits at river mile 24.9 inside the section and is the number to watch before committing to a trip.

Access thins compared with upstream. Launches at Salmon Fly FAS at the Melrose Bridge, Brownes Bridge, Kalsta Bridge, Glen, Notch Bottom at the Tony Schoonen FAS, Pennington Bridge, and High Road break the section into floatable pieces, but only one designated fishing access site exists between Glen and Twin Bridges, so the bottom floats are long, committing days — pick your takeout before you launch. The Burma Road, a dirt road paralleling the river from Glen nearly to Twin Bridges, is the practical way to scout and shuttle the lower water. The nearest town is Twin Bridges, and the nearest major airport is Bozeman Yellowstone, about two hours away.