River Park is a census-designated place (CDP) in St. Lucie County, Florida, United States.

The population was 5,222 at the 2010 census, at which time it was listed as Port St. Lucie-River Park.

It is part of the Port St. Lucie Metropolitan Statistical Area.

There were 2,698 housing units at an average density of 1,155.1 per square mile (446.0/km2).

31.4% of all households were made up of individuals, and 21.0% had someone living alone who was 65 years of age or older.