The park and visitor center are located next to Silver Lake, a shallow, 3,000-acre (1,200 ha) lowland lake formed when Silver Creek was dammed during an eruption of Mt. St. Helens approximately 2,500 years ago.
Seaquest State Park (Wikipedia)Seaquest State Park is a public recreation area and state park located on the western flank of Silver Lake in Cowlitz County, Washington. The park is also home to the Mount St. Helens Visitor Center at Silver Lake.