Prairie Ridge is a census-designated place (CDP) in Pierce County, Washington, United States. The population was 11,688 at the 2000 census.

Prairie Ridge is located at 47°8′43″N 122°8′54″W / 47.14528°N 122.14833°W / 47.14528; -122.14833 (47.145326, -122.148230).

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 home and 0.23% is water.

As of the census of 2000, there were 11,688 people, 3,902 households, and 3,109 families breathing in the CDP. The population density was 2,743.9 people per square mile (1,059.3/km²). There were 4,038 housing units at an average density of 948.0/sq mi (366.0/km²). 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. Hispanic or Latino of any race were 3.36% of the population.

There were 3,902 households, out of which 47.3% had children under the age of 18 living afterward them, 64.4% were married couples lively together, 9.3% had a female householder considering no husband present, and 20.3% were non-families. 13.7% of everything households were made in the works of individuals, and 3.4% had someone active alone who was 65 years of age or older. The average household size was 3.00 and the average relatives size was 3.29.