Blackfoot and American Falls reservoirs offer some of the best flat-water angling opportunities for trout in eastern Idaho.

If you’re like me, you might be getting the feeling that the winter season has dragged on long enough. While the winter season offers some outstanding hard-water angling opportunities, the open-water season offers abundant opportunities as well. Especially notable are the great trout fishing opportunities in the Southeast Region’s two largest reservoirs: Blackfoot and American Falls.

The open water season typically begins around the first week of May at Blackfoot Reservoir; however, the trout fishing usually doesn’t pick up until around the first week of June. Catch rates of both rainbow and cutthroat trout during this period can easily reach double digits per day. The average size of fish caught in the spring is around 18 inches, but trout weighing upwards of five pounds are not uncommon. The Idaho Department of Fish and Game stocks about 300,000 rainbow trout annually for anglers to harvest which pairs well with the general harvest rule of six trout per day; but remember, no cutthroat trout can be harvested from this reservoir.

Angling opportunities at American Falls Reservoir typically begin earlier than in its eastern, high elevation neighbor, Blackfoot Reservoir. Catch rates for rainbow trout can also reach double digits during the months of May and June. In addition to rainbow trout, American Falls also boasts a decent population of rainbow- cutthroat trout hybrids. In fact, the state record for this hybrid was harvested from the reservoir in 2011 and weighed nearly 35 pounds!  The high spring catch rates experienced by anglers are tied to the large number of rainbow trout stocked there annually—over a half a million! At American Falls, anglers can harvest a total of six trout per day, all species combined.

To target trout in Blackfoot and American Falls reservoirs, try trolling close to the surface and near the shoreline with some traditional pop gear or a flasher, trailed by a wedding ring spinner tipped with a little night crawler. Additionally, trolling a variety of spoons and crank baits (the author’s personal favorite) near the surface can also be quite productive. Having a fishing boat at your disposal does make access to these fisheries a bit easier; however, both reservoirs have several access areas that provide bank fishing opportunities. The best way to find these access points is to consult Fish and Game’s Fishing Planner (

Southeast Idaho has experienced average to above average snowpack levels over the past several years, and consecutive good waters years are paying dividends for fish populations in the upper Snake River drainage. What this means to anglers is there will be plenty of fish to catch this open water season. Your fish of a lifetime could be swimming somewhere in the Southeast Region, waiting for you.

Cutthroat x Rainbow Trout state record.jpg
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Photo by IDFG

In 2011, Mark Adams of Pocatello caught this state record hybrid trout from American Falls Reservoir.  It weighed almost 35 pounds and was just over 41 inches long.   Photo courtesy IDFG.