Pearl River County is a county located in the U.S. state of Mississippi. The population was 56,145 at the 2020 census. Its county seat is Poplarville.

Poplarville is a city in Pearl River County, Mississippi, United States. As of the 2010 census, the city population was 2,894. It is the county seat of Pearl River County. It hosts an annual Blueberry Jubilee, which includes rides, craft vendors and rodeos.