South Fork & Henry's Fork Fishing Reports

Contact us for up to the minute fishing reports and conditions.

Big Lost River

Jimmy's All Seasons Angler / Big Lost River

Big Lost River 7-9-19

Flows between 600-700 cfs coming out of Mackay Dam make for treacherous wading below.  If flow were cut in half, it would be safer for enjoying the golden stone and western green drake activity soon to come on. We still have no info on the river in Copper Basin, but USGS water flow gages tell us that Basin stream flows are are about normal.  So that alone suggests that good fishing should be available.


Big Lost River 7-2-19

Flow out of Mackay Dam is about 750 cfs making for very tough wading.  Hatchery catchables have been stocked at just above Arco. We have no information to date on fishing conditions on the river above the reservoir.


Big Lost River 5-9-18



We’ve had a few inquiries about Big Lost River fishing conditions just below Mackay Dam. Right now flow out of the dam is not far below 400 cfs making for difficult and dangerous wading there.  That’s about double normal flow for this date.  It might be a while before run-off and water demand allow for better wading conditions.



Big Lost River 8-28-17

We have not received much information on fishing the Big Lost River so far this year. Currently flow out of Mackay Dam is a bit higher than normal at around 350 cfs. Wading with caution is possible at this amount.  Terrestrial insect patterns should work during daytime hours with trico spinner falls during morning hours and caddis evening activity filling out chances for action at other times.


Big Lost River 7-28-17

The days of high water below Mackay Dam are gone until after the next winter of big snowfall. Flow just below the dam is where it usually is historically; around 500 cfs (about down to 0 cfs at Arco). This is a bit high for safe wading, but great for float-fishing.  We have no reports on fishing this part of the river, but safe to say woolly bugger types, your favorite bead head nymphs (especially as a dropper/trailer with Woolly bugger types), and streamers will work for now. Let’s wait until water drops more before good dry fly fishing kicks in.


Big Lost River 7-15-17

IDF&G is strongly considering a salvage regulation on the Big Lost River below Moore.  This is because as flows out of Mackay Dam decrease fish will become trapped in downstream pools and perish.  So rather than being wasted, salvage by legal means is being considered for the lower river. Go to the IDF&G web site for details on where this operation will be applied and for how long.


Big Lost River 5-20-17

It’s worth the time to drive to Arco just to see the Big Lost River doing something it has not done in decades. That is flow through town (currently 383 cfs) and beyond.  Flow out of Mackay Reservoir is currently 1300 cfs and has been at least as high for weeks, so it is no wonder that Arco is experiencing the river again.  This high flow below Mackay Dam makes approaching the river tough and fishing slow.


Big Lost River 8-23-16

Flow out of Mackay Dam is well over 300 cfs meaning wading immediately downstream should be done with some care. Early morning trico activity and late in the day caddis activity are providing action.  With flow at the current level, such as San Juan worms or small woolly buggers can bring action.