Pearl River is a town in St. Tammany Parish, Louisiana, United States. It is part of the New OrleansMetairieKenner Metropolitan Statistical Area. According to the United States Census Bureau, the town has a total area of 2.5square miles(6.6Square kilometers), of which, 2.5square miles (6.4Square kilometers) of it is land and 0.04square miles (0.1Square kilometer) of it (1.58%) is water. The community that is today Pearl River was originally known as Halloo, a moniker it reputedly garnered from loggers yelling to one another as they labored along the nearby Pearl River. Early Halloo was a small railroad town, located at the junction of the Northeastern and Poitevent and Favres East Louisiana Railroads.