Prairie Ridge is a census-designated place (CDP) in Pierce County, Washington, United States.

[2] According to the United States Census Bureau, the CDP has a total area of 4.3 square miles (11.1 km2), of which, 4.3 square miles (11.0 km2) of it is land and 0.23% is water.

As of the census[3] of 2000, there were 11,688 people, 3,902 households, and 3,109 families living in the CDP.

The racial makeup of the CDP was 93.38% White, 0.54% African American, 1.17% Native American, 0.91% Asian, 0.38% Pacific Islander, 0.79% from other races, and 2.84% from two or more races.

13.7% of all households were made up of individuals, and 3.4% had someone living alone who was 65 years of age or older.