Big Lost River

Big Lost River fishing report

Map, access and gauges for Big Lost River · Fish species · Hatches · Guides

No one has reported on this water recently. The report below is the most recent we have.

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Past outlook · Sep 30–Oct 7

This outlook’s window has closed. It is the most recent one we have for this water.

The Big Lost is shaping up as a solid afternoon destination for the week ahead on pleasant fall days. Flows are dropping as irrigation demands ease, ranging from 108 cfs in the upper section to 253 cfs below Mackay as of September 29, with further decreases expected. Low and frigid water means you'll want to fish midday when things warm, focusing on main stem and deeper runs below Mackay or shallow seams and riffles in the upper reaches once the day gets rolling. A dropping river creates opportunity: consider working heavier line and bigger attractors near the edges as flows settle and fish relocate into newly accessible water.

Read this outlook · All 11 outlooks

Conditions

Both upper and lower stretches of the Big Lost River are fishing well. Large Golden Stoneflies, Little Yellow Sallies, and thick PMD hatches are driving the action right now. These are solid pattern choices for the water.

Gauges

Live cameras

Big Lost River below Inlet Diversion near Arco

USGS 13132520 · Oct 18, 2026, 11:00 AM

Every 60 min · daylight

Big Lost River near Arco

USGS 13132500 · Oct 18, 2026, 11:00 AM

Every 60 min · daylight

Big Lost River near Leslie

USGS 13130300 · Oct 18, 2026, 11:00 AM

Every 60 min · 247

Big Lost River bl Mackay Res nr Mackay

Last updated

USGS 13127000 · Nov 7, 2025, 10:00 AM

Every 60 min · 247

Recommended flies

Golden StonefliesLittle Yellow SalliesPMDs