Situated on the shoreline of Hood Canal, the park features one of the warmest saltwater beaches in Washington state. This is because Hood Canal is one of the warmest saltwater bodies in Puget Sound. The name of the park derives from the Twana tribes, better known as the Skokomish, who made their home in the area. In 1922, the state leased 30 acres to be used as a state park, then after finalizing purchase of the property dedicated the park in 1923. The park serves as an example of buildings and structures that represent the Rustic/Arts and Crafts style, as executed by the CCC. Twanoh is popular for shellfish harvesting.

The name of the park derives from the word “twana” (Ind. “portage”). In the 1940s this area was sparsely populated and still retained much of its wilderness character. Startled pheasant and quail frequently whirred across the highway. Deer were often seen browsing in the open forest glades. In their frantic flight, they sometimes plunge recklessly in front of passing automobiles; markers caution the motorist to “Watch for Deer.”