Tamanowas Rock is said to have first been used 10,000 years ago by the Chimakum (or Chemacum) people (who no longer exist), leading to its alternate name Chimacum Rock, whose name is also found in other local geographic features. In accordance with legend, it may have been used as a refuge from the tsunami caused by the 1700 Cascadia earthquake, and earlier as a lookout for hunting now-extinct mastodon. Tamanowas means spirit power in the Klallam language.