Etna is a census-designated place (CDP) in Lincoln County, Wyoming, United States. The population was 123 at the 2000 census. As of the census of 2000, there were 123 people, 44 households, and 34 families residing in the CDP. The population density was 62.8 people per square mile (24.2Square kilometers). There were 55 housing units at an average density of 28.1Square meters (10.8Square kilometers). Etna is located Star Valley, a grassland valley surrounded by forested mountains. According to the United States Census Bureau, the CDP has a total area of 2.0square miles (5.1Square kilometers), all of it land.