Boulder is a census-designated place (CDP) in Sublette County, Wyoming, United States. The population was 170 at the 2010 census.
Boulder is located at 42°44′53″N 109°42′46″W (42.748164, −109.712828).
According to the United States Census Bureau, the CDP has a total area of 1.9 square miles (4.8 km2), all of it land.
As of the census of 2000, there were 30 people, 15 households, and 7 families residing in the CDP. The population density was 23.1 people per square mile (8.9/km2). There were 28 housing units at an average density of 21.5/sq mi (8.3/km2). The racial makeup of the CDP was 100.00% White.
There were 15 households, out of which 13.3% had children under the age of 18 living with them, 40.0% were married couples living together, 6.7% had a female householder with no husband present, and 53.3% were non-families. 46.7% of all households were made up of individuals, and 13.3% had someone living alone who was 65 years of age or older. The average household size was 2.00 and the average family size was 2.71.
In the CDP, the population was spread out, with 10.0% under the age of 18, 6.7% from 18 to 24, 30.0% from 25 to 44, 36.7% from 45 to 64, and 16.7% who were 65 years of age or older. The median age was 46 years.