Mesa Falls and the Henrys Fork: The Fly Fisherman's Cathedral

The Henrys Fork of the Snake River drains the western slope of the Yellowstone Plateau in eastern Idaho, flowing through the Caribou-Targhee National Forest before entering the Snake River Plain. It is considered by many fly fishermen to be one of the finest dry-fly rivers in North America, a judgment that rests on the size and selectivity of its wild rainbow trout, the clarity of its spring-fed water, and the insect hatches that emerge from its cold, clean current in volumes that reward patience and punish carelessness.

The Henrys Fork is spring-fed from large aquifers in the volcanic rock of the plateau. Its source, Henrys Lake, and the springs that feed its upper reaches maintain nearly constant temperature year-round, which means the insects that hatch from it do so in predictable cycles that experienced anglers can anticipate.

Downstream from the railroad ranch section where most of the famous trout fishing takes place, the river drops over Mesa Falls, the only undisturbed major waterfall remaining on any river in the Snake River system. The upper falls drop one hundred fourteen feet; the lower falls drop sixty-five feet. Both remain in their natural state because, unlike nearly every other major drop on the Snake and its tributaries, no dam was built here.

The Caribou-Targhee National Forest takes its hyphenated name from the merger of two separately administered forests in the twentieth century. The Targhee portion is named for a Bannock chief, Taigher, whose name was anglicized in the naming process.