Lewis River Fishing: Water Bodies, Seasons, and Access

A complete Lewis River fishing guide starts with one fact most visitors miss: this 93-mile system in southwest Washington behaves like five separate fisheries stitched together by water. Three PacifiCorp dams, Merwin, Yale, and Swift No. 1, fracture the watershed into Lake Merwin, Yale Lake, and Swift Creek Reservoir. The free-flowing lower river below Merwin Dam and the North Fork and East Fork above the reservoirs each run on their own seasonal clock.

This guide walks through each distinct section of the Lewis River, from the dam-formed lakes to the wild lower river, matching species, tackle, and timing to the water an angler actually plans to fish.

A Watershed Divided by Dams

Three concrete walls define this river. Merwin Dam sits roughly 22 miles upstream of the Columbia confluence, Yale Dam lies above it, and Swift No. 1 caps the system near the headwaters. Each dam backs water into a distinct reservoir, and each reservoir warms, cools, and stocks at a different rate.

Below Merwin, the lower Lewis tumbles through Clark and Cowlitz counties toward Woodland, picking up salmon and steelhead runs from the Columbia. Above the dams, the North Fork and East Fork run cold and clear through old-growth forest, holding wild cutthroat and summer-run steelhead. Recognizing which of these water bodies you actually plan to fish is the foundation every later decision, gear, season, license, and launch, depends on.

How Each Section Behaves

Lake Merwin stretches about 7 miles long with a maximum depth near 200 feet. Yale Lake runs shallower and warmer, and Swift Creek Reservoir sits at the highest elevation with the coldest, clearest water of the three. The lower river below Merwin changes character with the tides and the Columbia’s flow, while the forks stay narrow, rocky, and walkable most of the year.

Water Body	Primary Character	Target Species
Lake Merwin	Deep, stratified reservoir	Kokanee, landlocked coho, rainbow trout
Yale Lake	Shallower, warmer reservoir	Kokanee, rainbow trout, smallmouth bass
Swift Creek Reservoir	Cold, oligotrophic	Kokanee, trout (access can be limited)
Lower Lewis River (below Merwin)	Free-flowing, tidal influence near mouth	Chinook, coho, chum, pink salmon, steelhead, bass
North Fork & East Fork	Cold, wild trout stream	Cutthroat, rainbow trout, summer steelhead

“Tip: Before you drive two hours with a drift boat on the roof, confirm which dam controls the section you plan to fish. Water release schedules can swing reservoir levels by several feet in a single week.

Species You Can Target Across the System

Four Pacific salmon species enter the lower Lewis on staggered runs, and the timing varies enough that something is usually moving. Chinook show up first in spring, followed by coho, then chum, and occasional pink salmon in odd-numbered years. The lower river also holds the system’s main steelhead action, with summer fish entering the fish ladder at Merwin Dam and winter fish moving in from December through March.

Up in the reservoirs, the picture shifts entirely. Yale Lake and Lake Merwin both hold landlocked kokanee and coho that survive and reproduce without ever touching salt water. These fish suspend deep through summer and migrate toward the surface during spring and fall turnover. The North Fork and East Fork above the dams stay wild, with native cutthroat and rainbows feeding on mayflies, caddis, and the occasional summer steelhead fresh out of the Pacific.

Bonus Targets Outside Salmon Windows

Smallmouth bass have spread throughout the lower river and the tailrace below Merwin Dam, providing solid action when salmon runs go quiet. Largemouth bass show up in Yale Lake’s warmer coves, and yellow perch add a panfish option for kids and light-tackle anglers. If your timing is off for steelhead, the bass and perch keep a rod bending from May through October.

Knowing what’s biting is only half the picture,matching the rig to the river or reservoir is what turns a hopeful cast into a hookup.

• ▸Chinook salmon: Spring and fall runs, best in the lower river near Woodland
• ▸Coho salmon: Late summer through fall, plus landlocked fish in the reservoirs
• ▸Chum salmon: October through November, often overlooked but abundant
• ▸Steelhead: Summer run above Merwin, winter run below the dam
• ▸Cutthroat and rainbow trout: Wild fish in the North and East Forks
• ▸Kokanee: Suspending fish in Yale Lake and Lake Merwin
• ▸Smallmouth bass: Lower river and tailrace areas, plus Yale Lake coves

Matching Techniques and Tackle to Each Water Body

What works on Yale Lake in August will get you skunked on the North Fork in June. Trolling downriggers and lead-core line is the standard for kokanee in the reservoirs, where fish hold at 40 to 60 feet through the warm months. A flasher trailing a small hoochie or wedding ring spinner tipped with corn is the proven setup, and electronics matter here more than fly choice.

Drift fishing the lower river for fall Chinook calls for a different rig entirely. A standard 8.5- to 10.5-foot rod paired with a level-wind reel, 30-pound mainline, and a spread of three to five ounces of lead gets bait down where salmon travel. Cured salmon roe in mesh bags or plug-cut herring fished on a bait rig both produce, and bobber fishing roe under a float covers the shallower slots.

Steelhead and Trout Tactics

Summer steelhead above the Merwin fish ladder are the Lewis’s premier fly opportunity. A 13-foot Spey rod with a traditional wet fly like a Green Butt Skunk or a swung Intruder-style streamer covers the water and triggers takes from chrome-bright fish moving up through cooler months. Sink-tip lines in the 10- to 15-foot range match the river’s depth during summer low flows.

On the forks, scale down. A light spinning rod with 4- to 6-pound test, a small inline spinner such as a Panther Martin or Rooster Tail, and a careful approach keep wild cutthroat from spooking. During summer hatches, a 3- or 4-weight fly rod with a size 14 elk-hair caddis or parachute Adams draws consistent rises along the deeper pools.

“Expert tip: Wild steelhead in the Lewis must be released. Carry hemostats and a net with rubberized mesh, and keep handling under 10 seconds when you do land one.

Seasonal Timing and Why the Calendar Matters

Fall Chinook peak September through October in the lower river, and water temperature is the single best predictor of when a good week turns into a great one. When the lower Lewis drops below 58 degrees, salmon stack in the deeper holes near Woodland and the action stays consistent through the first heavy rain. Warm, dry Octobers push the run later, sometimes into November.

Summer steelhead arrive June through August on the upper river, while winter steelhead enter the lower river December through March. The two runs are managed separately, and the upper fishery closes earlier each year to protect wild fish heading for the hatchery.

Reservoir and Fork Calendar

Kokanee in Yale Lake and Lake Merwin bite best during spring and fall turnover, when fish abandon the thermocline and roam the upper 20 feet chasing. Trollers who switch from downriggers to lead-core line at 3 to 5 colors during turnover often double their catch. Trout fishing on the forks stays reliable from late May through early October, with mayfly hatches in June and caddis hatches in July driving surface activity through the warm months.

Season	Peak Target	Best Water Body
Spring (Mar–May)	Trout, early kokanee	Forks, Yale Lake
Early Summer (Jun–Jul)	Summer steelhead, bass	Upper river above Merwin, lower tailrace
Late Summer (Aug)	Kokanee, bass	Lake Merwin, Yale Lake
Fall (Sep–Nov)	Chinook, coho, chum	Lower river near Woodland
Winter (Dec–Mar)	Winter steelhead	Lower river below Merwin

Licensing, Regulations, and Where the Rules Shift

Anglers 15 and older need a Washington state freshwater license to fish the Lewis anywhere upstream of the mouth. If you plan to fish within the Columbia River zone near the confluence, a Columbia River endorsement is also required. Both are available through the Washington Department of Fish and Wildlife (WDFW) licensing system and most regional sporting goods stores.

Wild steelhead must always be released across every section of the Lewis. Only hatchery-marked steelhead, identified by a missing adipose fin, may be retained under current WDFW rules. Selective gear rules, size limits, and creel limits change annually, and they differ between the reservoirs, the lower river, and the forks, so checking the current WDFW sport fishing pamphlet before each trip is non-negotiable.

Tribal Co-Management and Emergency Rules

Cowlitz Indian Tribe authority over the lower Lewis basin means tribal regulations can open or close fisheries independently of state rules. Treaty gillnet fisheries upstream can affect catch rates downstream, and emergency rule changes mid-season are common. Subscribe to WDFW’s rule-change notifications and check the tribal fishing bulletin before every trip to the lower river.

Before plotting the launch, lock in the paperwork: permits and zone rules quietly decide which ramps and stretches you can actually fish.

“Warning: Selective gear rules on parts of the Lewis prohibit bait and restrict anglers to artificial lures or flies with single, barbless hooks. Bait fishing in a selective gear section can result in a fine even if your catch is legal.

Access Points, Boat Launches, and Trip Logistics

The lower river near Woodland offers the easiest bank access and several public boat launches suited to salmon anglers. Merwin Landing, Daybreak Park, and the launch near the Highway 503 bridge all provide parking and restroom access, though river levels can affect the usability of each site. Arrive early during the fall Chinook peak; prime spots fill by 6 a.m. on weekends.

Lake Merwin and Yale Lake each have designated launches with restrictions on motor size and seasonal water levels. Speelyai Bay boat launch on Lake Merwin and the Yale Lake launch off Highway 503 handle trailered boats through most of the year, though both can become shallow during late-summer drawdown. Swift Creek Reservoir requires checking current access status, because low-water years can limit launching and shore fishing, and the road in has been closed in past dry seasons.

Working With a Guide

Hiring a licensed outfitter is the fastest way to learn each water body, and most guides specialize by species and section. Drift boat trips on the lower river for fall Chinook typically run $400 to $600 for two anglers, while reservoir kokanee trips out of Yale or Merwin run $250 to $400 for a half day. Fly fishing for summer steelhead above Merwin runs higher, often $500 to $700 per day, but the instruction on Spey casting and reading the water is hard to replicate on your own.

• ▸Lower river salmon trips: Best booked August through October, two-angler minimum common
• ▸Reservoir kokanee trips: Peak April through June and again in September
• ▸Spey casting lessons: Often combined with summer steelhead trips, June through August
• ▸Trout on the forks: Walk-in access, no boat needed, June through September

“Tip: Call the launch you plan to use 48 hours before your trip. Reservoir water levels shift quickly in late summer, and a launch that worked in June can be unusable by August.

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