Yellowstone's Lewis River
The Lewis River is a tributary of the Snake River and is a popular destination for Yellowstone backcountry travelers, fishermen, and campers. The entire course of the river is located within the boundaries of Yellowstone National Park in Wyoming about 70 miles north of Jackson Hole. The river is named for Meriwether Lewis, commander of the Lewis and Clark Expedition though Lewis and Clark and the Corps of Discovery never saw Yellowstone.
The Lewis River begins at the southern end of Shoshone Lake and flows southerly approximately 3 miles to Lewis Lake; here the river is called the Lewis River Channel. The river reemerges at the southern end of Lewis Lake and flows in a general southerly direction through a steep canyon roughly paralleling the south entrance road toward the south entrance of the park. Shortly before leaving the park, the Lewis River merges with the Snake River just north of Flagg Ranch, changing its course southward. The Snake soon flows out of Yellowstone into Grand Teton National Park and Jackson Lake.
The Lewis River Channel is the only portion of the river where boating is permitted, and many canoers use the channel to access the camping at Shoshone Lake. The Lewis Channel is three miles long and is a fairly large stream. The trout in the Lewis Channel are brown trout that average 14 to 18 inches with a smattering of some larger ones for icing on the cake. There are also some lake trout in the channel as well. You can access the Lewis Channel by boat or from the Lewis River Trail at the Dogshead Trailhead. The trailhead is located about 8 miles south of West Thumb on the South Entrance Road. It is a three-mile hike to the channel. Be sure to bring your bug repellent, as mosquitoes and biting flies are fierce.
The river reemerges at the southern end of Lewis Lake where the Lewis River exits Lewis Lake, here is easily reached from the Lewis Lake campground and offers good fishing for brown trout and lake trout for a short way but soon access becomes difficult as there is no trail and steep cliffs and downfall make this section dangerous but if you try you will be rewarded with small fish that will make you question your judgment.
From Lewis Falls to Canyon Section the Lewis River for about two miles is smooth, slow flowing water that resembles a spring creek, with slow-moving meadow water, and large, wary, college educated, heavily fished, brown trout. Hatches of Pale Morning Duns, Green Drakes, and caddis, can coax these fish to the surface. In the late season, terrestrials also account for some big fish. This is major-league fly-fishing. Long leaders, fine tippets, and stalking skills are necessary for success.
The canyon section is very difficult to access and produces mostly small fish. When the Lewis River enters its canyon, access is nearly impossible due to the steep canyon walls and rock faces. The river flows through the canyon for several miles, until it joins the Snake River near the South Entrance. The dangers of climbing in and out with the absence of trails makes the canyon section, as tempting as it is, best left alone.
There is plenty of tempting whitewater in the Lewis River Canyon for whitewater enthusiast but it is illegal to kayak or raft on Yellowstone’s whitewater.