Etna
"Etna, a town on the north fork of Lewis River, in the northwestern part of Clarke County. When the postoffice was established in 1882 it was named after Etna Green, Indiana, at the suggestion of two old settlers, A.C. Reid and Nathan Davis, who had come from Indiana. 'I was present at the meeting when the name was selected.'" (A.P. Anrys, postmaster at Etna...)
Origin of Washington geographic names, 1923