Osage is a census-designated place (CDP) in Weston County, Wyoming, United States. The population was 208 at the 2010 census.
Osage is located at 43°58′59″N 104°25′27″W (43.982948, -104.424145).
According to the United States Census Bureau, the CDP has a total area of 1.9 square miles (5.0 km²), all of it land.
As of the census of 2000, there were 215 people, 101 households, and 61 families residing in the CDP. The population density was 111.0 people per square mile (42.8/km²). There were 124 housing units at an average density of 64.0/sq mi (24.7/km²). The racial makeup of the CDP was 96.74% White, 2.79% Native American, and 0.47% from two or more races. Hispanic or Latino of any race were 0.93% of the population.
There were 101 households out of which 20.8% had children under the age of 18 living with them, 48.5% were married couples living together, 6.9% had a female householder with no husband present, and 39.6% were non-families. 34.7% of all households were made up of individuals and 14.9% had someone living alone who was 65 years of age or older. The average household size was 2.08 and the average family size was 2.62.
In the CDP, the population was spread out with 19.5% under the age of 18, 7.9% from 18 to 24, 24.7% from 25 to 44, 28.8% from 45 to 64, and 19.1% who were 65 years of age or older.