Whitehorse is a census-designated place (CDP) in Dewey County, South Dakota, United States.

[3] According to the United States Census Bureau, the CDP has a total area of 2.7 square miles (6.9 km2), all land.

The racial makeup of the CDP was 2.84% White, 94.33% Native American, and 2.84% from two or more races.

16.2% of all households were made up of individuals, and none had someone living alone who was 65 years of age or older.

There were 60.0% of families and 56.6% of the population living below the poverty line, including 61.5% of under eighteens and 40.0% of those over 64.