Picturesque mountain clear water deep Merwin Lake with evergreen coniferous forests on the mountains and the curvy shore

Lake Merwin, Washington

Lake Merwin is a reservoir formed by the construction of Merwin Dam on the Lewis River at the boundary between the Clark and Cowlitz Counties in the US State of Washington. The lake has 51 km of shoreline, numerous inlets, and a peaceful and tranquil upper arm. The upper arm is actually a section of the original Lewis River, which used to flow freely through the valley before the construction of the Merwin Dam. The waters of Lake Merwin are renowned for being extraordinarily deep, and the Kokanee fishing here is among the greatest in the Pacific Northwest. Being an oligotrophic lake, the waters of Lake Merwin have a high concentration of dissolved oxygen and few accumulated nutrients.

Geography Of Lake Merwin

Lake Merwin view in southwest Washington
Lake Merwin view in southwest Washington. 

Lake Merwin is about a two-hour drive from the state capital Olympia, a three-hour drive from Seattle, and roughly an hour from either Vancouver, Washington, or Portland, Oregon. Covering an area of 15.9 sq. km, Lake Merwin is roughly 14.5 miles long and reaches a maximum depth of 190 m. It holds a water volume of 0.521 cubic kilometers and has a catchment area of 1,890 sq. km. The lake receives water not only from the Lewis River but also from Speelyai, Brooks, Buncombe Hollow, and Marble Creeks.

Brief History Of Lake Merwin

The bottom of Lake Merwin used to be rich farmland with pear orchards and old-growth forests. Generations of people have lived in and grown their families in the valley since it was first inhabited in 1870. Families listed their farms for sale as the cities expanded, and the Northwestern Electric Company gradually acquired them. In 1931, the construction of the Merwin Dam was completed leading to the creation of the Merwin Lake. After the valley's old-growth trees were felled and the dam's gates were closed in 1950, the river started to rise. Homes were flooded first, and then the blooming locust trees vanished. The locust trees are claimed to still stand at the lake's bottom today.

Fishing In Lake Merwin

Father-daughter duo in life jackets with a husky dog rowing in a kayak boat in Merwin Lake
Father-daughter duo in life jackets with a husky dog rowing in a kayak boat in Merwin Lake.

One of the most fantastic spots in Southwest Washington for catching kokanee is Lake Merwin, which is also the only location close to Portland and Vancouver where you can capture a huge tiger muskie. In 1995, tiger muskies were planted to aid squaw fish population management. Kokanee, bull trout, coho, chinook, northern pike, and minnow are among the fish species found in the lake. Early spring is the ideal time to go fishing in Lake Merwin.

Recreational Activities In Lake Merwin

Vacationers begin to arrive for a three day weekend at Lake Merwin in Amboy, Washington
Vacationers begin to arrive for a three day weekend at Lake Merwin in Amboy, Washington. Editorial credit: photomatz /

Lake Merwin is a stunning and tranquil reservoir where boaters can observe both the sunrise and sunset. The lake is also an excellent area for inexperienced and beginning kayakers and stand-up paddle boarders to get their feet wet. Due to its proximity to towns and cities, the reservoir makes a fantastic day trip destination. Merwin Lake Park is another option. There are 135 picnic tables, two covered picnic shelters, a playground, water, restrooms, and chances for swimming and outdoor games. This park can house up to 1,500 people and is quite big.


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