Merrill Lake

Merrill Lake was formed when lava flows from Mt. St. Helens blocked the stream valley. In the early 1930s the lake was planted with Eastern Brook Trout, Rainbow Trout and Yelowstone Cutthroat. Brown Trout were introduced in 1987 and have proved to be very successful.

This fly-fishing, catch-and-release-only lake is located north of Cougar near Mount St. Helens. It is open to fishing year-round, but action is usually slow and often inaccessible during the winter months due to snow. Merrill contains Coastal Cutthroat, Brown Trout to several pounds and some Rainbow Trout.

The lake was stocked in 2018 with catchable Rainbow Trout.

Two-pole fishing is NOT allowed

Special fishing restrictions:

  • Fly fishing only for this lake

Shoreline access: Good - Shore access is available as the water level drops during the spring.

Species you might catch

Lake information

County: Cowlitz
Acreage: 283.40 ac.
Elevation: 1524 ft.
Center: 46.094333, -122.324233
Open in Google Maps

Find lowland lakes

View larger map

Fishing resources

Catchable fish plants
Release Location: MERRILL LK (COWL)
Stock Date Species Number Released Number of Fish Per Pound Facility
Apr 24, 2018 Rainbow 1,500 2.5 MOSSYROCK HATCHERY
Apr 13, 2015 Brown Trout 2,000 2.8 VANCOUVER HATCHERY
Apr 18, 2013 Rainbow 224 0.7 TROUT LODGE COMMERCIAL
Jul 5, 2011 Rainbow 2,145 3 MOSSYROCK HATCHERY
Apr 12, 2011 Rainbow 224 0.67 TROUT LODGE COMMERCIAL
Apr 24, 2009 Rainbow 224 0.17 TROUT LODGE COMMERCIAL
May 21, 2008 Rainbow 224 0.78 TROUT LODGE COMMERCIAL
May 7, 1997 Brown Trout 2,970 2 VANCOUVER HATCHERY
Visit the Catchable Trout Plants page for a more detailed search of trout plants in other bodies of water. To view and download the source data for this table visit the WDFW Fish Plants dataset on data.wa.gov.

Fishing prospects calendar

Rainbow trout

Fishing success for Rainbow Trout is generally best in the spring when thousands of fish are stocked statewide, but they can be caught year-round in most waters with a little patience and persistence. Success remains high into June and gradually declines as water temperatures increase and fish move offshore to stay cool. Fish that escaped the spring harvest return to the nearshore areas in the fall as waters cool off. Some waters may also be stocked again in the fall further boosting catch rates.
Chart showing fishing prospects throughout the calendar year

Coastal cutthroat trout (resident)

Fishing is best for Coastal Cutthroat in the spring and fall. There is a summer lull as fish move offshore into deeper waters to escape the summer heat in July and August. Catch is lowest in the late-winter while adults are spawning in tributary streams.
Chart of fishing prospects throughout the calendar year