Stillwater fly fishing can be intimidating, especially on a body of water like Henry’s Lake. Spanning 6,000 acres, it’s a large lake that doesn’t make things easy. Opportunities to catch trout from shore are limited, and the mucky bottom makes wading a sticky proposition. Plus, with its location just a few miles from the Continental Divide at 6,470 feet, it’s not unusual for the weather to shift dramatically, with sturdy gusts of wind blowing float tubes right off the lake.
But anglers keep coming back, and there’s a simple reason for that. Henry’s Lake has trout. Big ones. And lots of them.
Henry’s Lake is a natural lake, more or less. The lake was enlarged with the construction of a dam for irrigation in 1923, effectively doubling its size and depth (it currently maxes out at about 28 feet). The headwaters of the fabled Henry’s Fork of the Snake River, Henry’s Lake is itself fed by numerous springs and small tributaries, and it offers opportunities to catch some of the largest trophy trout in Idaho.
Trophy Trout Species in Henry’s Lake
Henry’s Lake has been managed as a trophy trout lake since the 1970s. The original focus was on Yellowstone cutthroat trout, and it continues to be a tremendous cutthroat lake. The growth rate of the fish is exceptional, with an average 4-year-old cutthroat trout on Henry’s Lake measuring 16 inches.
But these days, Henry’s Lake is arguably best known for cutthroat-rainbow hybrids, known as cutbows. Growing larger and faster than either of their parent species, cutbows in Henry’s Lake often reach 18 or 19 inches at four years old, and individuals up to 40 inches have been caught here. They’re also known for being less cautious and more aggressive than most other trout.
The final ingredient that makes Henry’s Lake special is brook trout. And not the dainty 8 to 10-inch brookies that populate mountain creeks, but hefty lake-dwelling brook trout that can measure 20-plus inches and attain football-like girth thanks to the fertile lake’s abundant biomass.
Seasonal Strategies for Fishing Henry’s Lake
The ideal approach to fishing Henry’s Lake depends on the season. The Idaho Department of Fish & Game opens the official fishing season on Memorial Day weekend—prior to that date, the fishing is strictly catch-and-release—and the weeks right after the season opener are some of the best, assuming the ice is gone.
Ice melts late here, often right around Memorial Day. The period immediately after ice-out is one of the only times to reliably find trout close to the bank. So if you’re planning on shore fishing, it pays to get here as soon after ice-out as possible. The other good time to find trout within casting distance of shore is fall, when brook trout stage a false spawn near creek mouths.
The rest of the non-frozen season, trout mostly feed in open water. And because wading is difficult around most of Henry’s Lake, the best way to target them is with a boat or float tube. If you do want to do some wading, your best bet is along the north shore.
In general, some of the best places to start fishing Henry’s Lake are areas around the mouths of creeks, including Duck, Hope, Howard and Targhee creeks. Again, some kind of watercraft will be needed to access the best spots, with kickboats, float tubes and pontoon boats being popular options. Other key spots are the mid-lake springs that seep up from the lake bottom, especially in summer. A good depth map of Henry’s Lake will show their locations.
Effective Stillwater Fly Fishing Techniques at Henry’s Lake
To put it simply, Henry’s Lake is not a dry fly fishery. Although there are some significant insect hatches here, it’s unusual to find consistent success luring trout to the surface. There are just too many delicious creatures for them to eat down near the bottom.
Most of the time, you’ll be fishing 10 to 20 feet below the surface. Sinking lines are standard here, and leech patterns are the most consistently effective flies. I’ve heard it said that leeches and tiny baitfish make up 50% of the diet for trout over 16 inches. So tie on a Simi Seal Leech, Seal Bugger or good old-fashioned Wooly Bugger in size #6 or #8. Hot colors tend to be olive, brown and cinnamon, though white can also be very effective some days.
Worth keeping in mind is that almost all of the lake bottom is carpeted in weeds, and trout typically feed right above the vegetation. Learning to count down your fly to just above the weed line will pay dividends. Once your presentation is at depth, work the fly back towards you horizontally above the weeds using short strips.
Occasionally, trout don’t take streamers like they usually do, and that often means something else is hatching. Midge emergences take place regularly on Henry’s Lake early in the season, and when that happens, trout will fall for a midge emerger pattern (size #16 to #20) on a sink-tip line with a strike indicator.
Arguably the most important hatch is the damselfly hatch, typically starting in late June and extending well into July. During this hatch, damselfly nymph patterns in sizes #10 to #12 will outfish just about anything.
Access Points and Facilities at Henry’s Lake
A lot of land around Henry’s Lake is privately owned, but there are still several good access options. These are the best places to access Henry’s Lake:
Henry’s Lake State Park
At the southeast corner of the lake, Henry’s Lake State Park is a popular area to fish near Howard Creek. The park has boat ramps and docks, and trout are known to congregate offshore.
Henry’s Lake State Fish Hatchery
The Henry’s Lake State Fish Hatchery overlooks the north shore of the lake just off Highway 87. A great area for fishing in spring and fall, the hatchery offers bank access and a picnic area; there’s no boat ramp, but you can put in a float tube or kick boat here. Watch for the roped-off ‘no fishing’ area near the hatchery.
Frome County Park
On the northeast side of the lake, Bill Frome County Park offers a free RV campground plus bank access and boat ramps. This is another spot where bank fishing is good around ice-out and in the fall.
Henry’s Lake Boat Access
Sometimes referred to as the South Shore Access, the Bureau of Land Management maintains a free public boat ramp with bank fishing access on the south end of the lake near Hope Creek. The ramp is undeveloped and best suited to small boats.