Steamboat Rock State Park, Nature reserve in Grant County, Washington, United States.

Steamboat Rock State Park is a nature reserve near Banks Lake featuring a distinctive columnar basalt rock formation and extensive waterfront access. The site provides campsites, hiking trails, and multiple boat launch areas for water recreation.

During the last ice age, ice dams diverted the Columbia River and Steamboat Rock stood as an island in the new riverbed. When the dams broke, massive floods carved the Channeled Scablands, the river returned to its old course, and the butte was left rising 800 feet above the dry Grand Coulee. Its plateau, over 600 acres, was later used by nomadic Native American tribes and early settlers.

The columnar basalt formations have long drawn people to study and experience the landscape shaped by ancient geological forces. Visitors can observe how the rock formations influence where people gather and what activities the place supports.

The park is most accessible in spring and fall when temperatures are mild and the area feels less crowded. Visitors should know that snow in winter can limit access to some areas.

The butte's flat plateau covers more than 600 acres and was used by nomadic Native American tribes and early settlers. During the last ice age the monolith stood as an island in the diverted Columbia River; when the ice dams burst and carved the Channeled Scablands, the river returned to its old course and left the rock in the dry Grand Coulee.