Etna is a census-designated place (CDP) in Lincoln County, Wyoming, United States. The population was 164 at the 2010 census.
Etna is located at 43°2′0″N 111°0′58″W (43.031124, -111.016042). in Star Valley, a grassland valley surrounded by forested mountains.
According to the United States Census Bureau, the CDP has a total area of 2.0 square miles (5.1 km2), all land.
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 (24.2/km2). There were 55 housing units at an average density of 28.1/sq mi (10.8/km2). The racial makeup of the CDP was 93.50% White, 1.63% African American, 1.63% from other races, and 3.25% from two or more races. Hispanic or Latino of any race were 4.88% of the population.
There were 44 households, out of which 45.5% had children under the age of 18 living with them, 65.9% were married couples living together, 9.1% had a female householder with no husband present, and 20.5% were non-families.