Stellar Cast Serious trout fishermen should make the trek to Idaho, whose array of waters offers more opportunities than any other state in the Lower 48

June 06, 2004

A good way to start fly-fishermen arguing is to ask them to name
the best trout water in Idaho. Up north in the panhandle there's
the St. Joe and the Coeur D'Alene, great places to catch native
western cutthroat on dry flies. The Middle Fork of the Salmon is
unmatched for its remoteness and sheer beauty, while Silver
Creek, near Sun Valley, gets the vote of skilled anglers with an
eye for big rainbow cruising in water clear as gin.

Floating the South Fork of the Snake is a good way, using a
grasshopper pattern, to catch trophy browns lurking beneath the
banks. The Clearwater ... the Blackfoot ... the list goes on.
With its sparse population and vast mountainous terrain, Idaho
boasts more great trout fishing than any other state in the Lower
48, all of it open to the public. If you can get to it without
trespassing, you can wade it. Adventurous fishermen willing to
hike can spend a lifetime in the Gem State and never fish the
same pool twice.

But if one name stands out, most agree it's the Henry's Fork,
Idaho's signature fly-fishing river. With its variety of water,
prolific hatches, scenery and selective, big-shouldered rainbow,
the Henry's Fork is one of the great treasures of the American
West. Named after a trapper who settled the area in the 1820s,
the Henry's Fork--sometimes called the North Fork of the Snake
River--is a giant spring creek whose flow is controlled by a
series of dams. It originates at Henry's Lake in a notch of the
Continental Divide, a few miles south of the Montana border, just
west of Yellowstone Park. The primary headwaters of the Henry's
Fork, however, flow into the river at Big Springs, some 12 miles
south of the lake, where 120 million gallons of 52° water bubble
to the surface 365 days a year, making it one of the 40 largest
springs in the U.S.

Big Springs serves as both spawning area and nursery for the
brawny rainbow that dominate the trout population in the Henry's
Fork (they were introduced to the watershed in the early 1900s,
and soon overwhelmed the native Yellowstone cutthroat), so
fishing has been prohibited in Big Springs since 1919. But on the
viewing platform wide-eyed fishermen can ogle giant rainbow as
they cruise through the mossy tendrils that wave in the current
like long locks of hair. Trout weighing more than 18 pounds have
been caught in the Henry's Fork, and several exceeding 10 pounds
live at Big Springs. Thousands of their offspring in the four- to
five-pound range can be found in the 117-mile stretch between
Henry's Lake and Menan, where the Henry's Fork joins the main
branch of the Snake River. That's why anglers from as far away as
Southeast Asia come to fish.

"The Henry's Fork offers every kind of fly-fishing there is,"
says Pat Bennett, a guide for Hyde Outfitters, one of seven guide
services licensed to float the river in drift boats and rafts.
"Spring creek, freestone, tailwaters, rapids. Nymphs, dry flies,
streamers. Wading, drifting, sight fishing."

Bennett, who spent 22 years in the U.S. Army before retiring in
1997 as a lieutenant colonel, has been fishing the Henry's Fork
since 1970. "The upper portion of the river was incredible then,"
he says. "It goes in cycles."

The cycles, many guides believe, are directly related to the
amount of water released from the Island Park Dam (some 30 river
miles south of the Henry's Fork's headwaters), which was built in
1935 for irrigation purposes. In a dry year the level of the
Island Park Reservoir is kept up all winter so potato farmers
will have access to its millions of gallons during the growing
season. Less water flows downriver, which adversely affects the
populations of both the trout and the insects they feed on. In a
wet year, when the snow pack is deep, the volume of water flowing
out of the dam in the winter months increases, and the level of
the river rises. "In '98, '99 and 2000 there were good flows all
winter long, and those years we were catching 35 to 40 fish a
day," Bennett says. "With the drought, we're in a down cycle now.
A good day is 20 hookups."

Twenty hookups of strong, wild rainbow is a good day for most
fishermen, and we had such a day in the first week of last July.
Bennett took my wife, Sally, and me down Cardiac Canyon, a
tumbling 19-mile stretch of the Henry's Fork just below the Mesa
Falls. Upper Mesa Falls drops 114 feet, Lower Mesa Falls 67 feet;
there's no campground or boat access along the stretch below
them, so Cardiac Canyon is a tough place to get into or out of.
Bennett skidded his raft down to the river on an impossibly steep
slope--I was certain the man was suicidal--but once we were
floating, we were rewarded with wild solitude. A moose and her
calf bounded along the banks of the river. A bald eagle perched
watchfully in the top branches of a ponderosa pine. The water was
a trout-friendly 58°, and the current so strong that the few
times we got out to wade, we staggered and braced ourselves
against being washed away with every baby step. In the raft we
drifted swiftly between the boulders, casting into the riffles
and seams. We landed a couple of whitefish, which are prevalent
throughout the river, and the first trout I caught was my best of
the day. It was an 18-inch rainbow whose silver body was so thick
I could barely put my hands around it. It looked almost deformed,
the salmonoid equivalent of a linebacker with no neck. It was a
classic Henry's Fork fish.

The next day we began our float farther upstream, through Box
Canyon, which begins just below the Island Park Dam. It is easily
accessible from a boat launch and thus more heavily fished. But
it begins an unforgettable 20-mile stretch of water. For the
first three miles the canyon walls press upon you, and great
pines grow to the water's edge. Giant boulders are scattered in
the river, creating pockets and eddies that hold big fish.
Gradually the canyon walls begin to break down, and the river
starts to open up. The water is loaded with stone fly
nymphs--big, brown cockroach-sized bugs--and our guide this day,
62-year-old Ken Soares, regaled us with stories of what it's like
when those stone flies hatch in late May or early June. "The
trout eat so many, you can see the outline of the nymphs in their
stomachs," Soares said. "They throw up on you when you're
unhooking them, or sometimes two or three real flies are in the
trout's mouth with your artificial, trying to crawl out and get
away. Piggy, piggy."

Soon the river grows even wider, the current slackens, and the
vistas begin opening up. At the mouth of the canyon is a curve of
wadable water called Last Chance Run, which flows into the most
famous stretch of water on the Henry's Fork: the Railroad Ranch.

The Ranch, as it's affectionately known, is part of Harriman
State Park, donated in 1977 to the people of Idaho by the
Harriman family of Union Pacific railroad fame. A waterfowl
refuge whose species include the rare trumpeter swan, the Ranch
is open for fishing only after nesting season, from June 15 to
Sept. 30. But once open, this nine-mile stretch of meandering
flatwater is as good as dry fly-fishing gets. At dusk, as the sun
turns the Western sky to fading embers, the surface of the river
comes alive. Thousands of trout and whitefish, many trophy-sized,
quietly and rhythmically begin to sip down hatching insects,
dappling the water's dark surface like drops of rain. "These
trout all have Ph.D.'s," Soares had warned us. "They've been
fished over so often that they're very smart. You go in with the
idea of catching one fish. You see one working, figure out what
he's doing, and it's very, very fun."

The nights we fished the Ranch, the surface was blanketed by dead
and squirming insects, broken only by the occasional nose of a
sipping trout. Without moving my feet, I could cast to any of a
dozen feeding fish. A few hundred yards downstream, Sally was
casting to a dozen more. We kept changing flies, watching our
drifts, squinting into the fading light. Was that rise to the
dried fly on my line, or to a natural bug nearby? The fish kept
it up for more than an hour, steady, relentless, selective,
giving us dozens, no, hundreds, of drifts. I caught one trout, a
football-sized rainbow.

The Ranch was very, very fun.
For more about sports in Idaho and the other 49 states, go to

This is the 46th in SI's 50th anniversary series on the 50
states. Next week: Nebraska.

TWO COLOR PHOTOS: PHOTOGRAPHS BY DAWN KISH AS GOOD AS IT GETS The Ranch is an especially alluring section of the Henry's Fork, the state's signature fly-fishing river. TWO COLOR PHOTOS: PHOTOGRAPHS BY DAWN KISH PICTURESQUE The remoteness of majestic Lower Mesa Falls makes for an ideal angling locale.

"These trout all have Ph.D.'s. You go in with the idea of
catching one fish. You see one working, figure out what he's
doing, and it's very, very fun."