Bismark Reservoir in Madison County: How and When to Fish It

• Overview

  The Madison County end of Montana holds Bismark Reservoir. Height above sea level is 7,559 feet. The whole thing is a single swim; walk it in a minute. Our Madison County list holds plenty of bigger water. Some 18 miles away sits Whitehall, the nearest settlement. Beyond it, Three Forks at 31 miles and Butte at 36 miles. The nearest boundary is well away, so one set of rules covers the water.

• Where to Fish on Bismark Reservoir

  Nothing we hold settles how deep this runs. Where the bottom changes texture, fish gather; find that line. A natural lake fishes on cover, and cover here means weed and timber. County-wide records name rainbow trout, brown trout, mountain whitefish, brook trout and california golden trout. What holds for the county may not hold for this water. The shape of Bismark Reservoir decides where the fish sit.

• Seasonal Patterns

  In an average year July sits at 53°F and January at 18°F. The year splits cleanly: hard water, then open water. Once it clears, about late May, the fishing comes on quickly. Break-up sits around late May on average, with the water closing again about mid November. The strongest runs come at either end of the open season. Bismark Reservoir runs to that rhythm year in and year out.

• Tackle & Baits

  Ownership and access are not documented in what we hold. You can park half a mile away and walk in from there. For the trout, small spinners and a box of nymphs cover both approaches. Local rules can differ across the county line, so check where you stand. Where the way in crosses private ground, ask first. Louise Lake sits 0.9 miles off and takes the overflow. Where Bismark Reservoir is concerned, a local answer beats a written one.