Tamanowas Rock, Sacred ceremonial rock formation in Jefferson County, United States.

Tamanowas Rock is a massive stone formation that rises approximately 150 feet above the surrounding forest, with caves, crevices, and moss-covered surfaces throughout. The rock sits near Anderson Lake State Park and displays layered geological features shaped by ancient volcanic activity.

The site held importance for people over 10,000 years ago, who used high vantage points to hunt game in the surrounding lands. It later provided refuge when a major tsunami struck the coast in 1700.

The Klallam name Tamanowas means "spirit power", and the site is a pilgrimage destination for Coast Salish peoples. The Jamestown S'Klallam Tribe bought the rock and 62 acres around it in 2013 to protect it, adding the land to an earlier 22-acre purchase. Graffiti daubed on the rock in 2014 drew national and international attention.

The rock stands in forest next to Anderson Lake State Park, near Port Townsend in Jefferson County. Since the Jamestown S'Klallam Tribe bought the site in 2013, climbing has been stopped, so the formation is not a climbing destination. The tribe owns the rock and 62 acres around it, added to an earlier 22-acre purchase; visitors should treat the ground as a sacred site.

The rock is Eocene subaerial adakitic lava and lava breccia. Dikes of similar composition lie in the Blue Hills near Bremerton, 60 km away; geologists link both to subduction of the Kula-Farallon Ridge beneath North America, though they may be one magmatic arc, two isolated volcanic centres, or one centre displaced along a Puget Sound fault.