Updated
Idaho Lakes › Upper Snake / Eastern Idaho
Mackay Reservoir
A high-desert irrigation reservoir on the Big Lost with stocked rainbows and self-sustaining kokanee.
Rainbow Trout
Cutthroat TroutOverview
Best Season
Late spring through July while the pool is full, and late-winter ice fishing for kokanee.
Lake Character
Open, windy irrigation reservoir that drops steadily through the irrigation season.
Skill Level
Beginner friendly from shore or a boat, kokanee timing rewards patience.
Best Techniques
Troll or jig for kokanee, bait from shore for rainbows, streamers and nymphs near the inlet.
Boat Access
Custer County ramp and dock at BLM's Joe T. Fallini site, plus IDFG upper and lower ramps.
Kokanee and Rainbows Below Mackay Peak
Mackay Reservoir sits at 6,060 feet in the Big Lost River Valley, five miles north of Mackay on US 93. IDFG stocks catchable rainbows each spring and the kokanee reproduce on their own, with high catch rates the norm in many years. Trolling and jigging take kokanee once the water warms, shore anglers work the ramps and points, and fly anglers do best on the inlet and shallow edges in spring and fall. Ice fishing for kokanee and trout is popular in late winter. This is an irrigation reservoir owned by the Big Lost River Irrigation District, so expect a steady drawdown from July, and in low or work years the ramps go dry and float tubes are the call, as they were in September 2025. No special rules apply, the general trout limit is six and kokanee fifteen, but IDFG has issued no-limit salvage orders here twice, so check the current rules. Launch at BLM's Joe T. Fallini Recreation Site or the IDFG upper and lower access sites.
Conditions
Live water levels for Mackay Reservoir from linked gauge stations.
Access
Regulations
No documents attached
Regulation PDFs and lake maps will appear here when published. Always verify current rules with IDFG.
IDFG regulationsGuides & Outfitters
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Helpful Links
Water data is read live and updated regularly. Level and storage trends are calculated from recent daily readings; fields shown as unknown or unavailable have no current data.