Seaquest State Park, Public recreation area at Silver Lake, Washington, United States.

Seaquest State Park is a 505-acre recreation area on the western shore of Silver Lake in Cowlitz County, Washington. It has a one-mile shoreline on the lake, a second-growth evergreen forest of Douglas fir, hemlock, alder and aspen, and a pedestrian tunnel under Spirit Lake Memorial Highway linking the park to the Mount St. Helens Visitor Center.

Swedish settlers led by Charles John Seaquest began a homestead on the land in 1870. The family donated the site to Washington state in 1945, under Alfred L. Seaquest's will, with a clause barring liquor sales; a violation would transfer the original parcel to Willamette University. A $20,000 state allotment in 1952 started work, and the park opened in April 1954. The Mount St. Helens Visitor Center opened on December 13, 1986, and passed fully to the state in 2007.

The visitor center displays art and educational materials showing how the Cowlitz Tribe has been connected to this region for generations. These exhibits help guests understand the indigenous heritage of the area.

The park offers camping options, rental accommodations, and hiking trails suited for different abilities. The lake provides opportunities for boating and fishing, with facilities arranged to accommodate various visitor needs.

A boardwalk extends through the wetlands and lets visitors observe wildlife while learning about the local ecosystem. This elevated pathway protects the delicate habitat while providing close encounters with nature.