Directions
Holter Lake MarinaThe Gates of the Mountains Marina is located on the south end of Holter Lake about 20 miles north of Helena, Montana. The marina is the hub for scenic boat tours and recreational access the Land of the Giants in the Missouri River canyon. It features a public boat launch, private slips, a gas dock, and a restaurant.
Fly Fishing the Missouri River Land of the Giants
The Land of the Giants runs roughly 4 miles from just below Hauser Dam downstream into the upper end of Holter Lake, forming a highly productive tailwater reach. Cold, consistent releases from Hauser Dam create stable flows and rich aquatic insect life, allowing rainbow and brown trout to grow to exceptional sizes.
Steep rock canyon walls dominate much of this section, especially as the river passes through the Gates of the Mountains area, giving anglers dramatic views of cliffs and rock formations that inspired the reach’s name. The Missouri River here is broad, fast, and deceptively deep in many runs, with strong mid-river currents, shelves, and buckets that concentrate big fish.
River Access
Access to the Land of the Giants is primarily by boat rather than by road, which keeps pressure relatively controlled despite the reach’s reputation. Anglers typically launch at the Gates of the Mountains Marina on Holter Reservoir and run upriver in jet boats or power drifters to the tailwater section below Hauser Dam.
The Land of the Giants earned its name from the high densities of large trout. Rainbow trout dominate in numbers, but hefty browns are present, particularly close to the dam and in deeper slots. Consistent cold water and food-rich currents mean fish can reach “trophy” sizes that justify the “Giants” moniker, with many trout well into the high‑teens and twenties in inches.
Nymphing Tactics
Nymphing is a highly effective way to fly fish in the Land of the Giants and often the most consistent way to catch the larger trout. Productive nymph rigs on this stretch of the Missouri River are typically two-fly setups with sowbugs, scuds, midge larva, caddis pupa and small mayfly nymphs in sizes roughly 12–20, often weighted or paired with split shot to reach the deep slots. Also effective are larger attrator nymphs or large San Juan Worms patterns
It's recommended to run relatively short but stout leaders (2X or 3X) with adequate weight to quickly reach depth. Also be sure to adjust indicator position frequently as depth changes from flats to buckets. How your boat is positioned is critical: long, controlled drifts down current seams, drop‑offs, and tailouts of big runs let flies drift naturally where large fish feed.
While nymphing is highly effective, the Missouri River offers anglers opportunties for technical dry‑fly and emerger fishing when hatches line up. During blue-winged olive, midge, or summer mayfly hatches, pods of big trout set up on foam lines and softer edges along gravel bars and banks, sipping emergers and duns.
Dry flies in the 16–20 size such as parachute mayflies, CDC emergers, and low‑riding midge patterns are effective, often fished on long 9–12 foot leaders with finer terminal tippet. Success usually comes from carefully targeting individual risers, using reach casts and slack‑line presentations to avoid drag in the complex, intersecting currents.
