Historical marker No. 530, on Etna Road just east of NE 47 about 19 miles south of Arnold, recalls Etna, whose post offices ran from 1885 to 1921 and whose school, store and telephone exchange served the area from 1907. It was erected in 2017 by the Custer County Historical Society, the Etna community and the Nebraska State Historical Society. A mailbox at the marker holds a history and a guest book.