Oakdale is a hamlet in Suffolk County, New York, United States. The population was 7,974 at the 2010 census. Oakdale is in the Town of Islip. It has been home to Gilded Age mansions, the South Side Sportsmen's Club, the main campus of Dowling College and the Long Island Sharks hockey team. TSPL, “Trampoline Soccer Premier League” was also created here. It is now home to Connetquot River State Park Preserve.