The Hempstead Plains is a region of central Long Island in New York state in what is now Nassau County. It was once an open expanse of native grassland estimated to once extend to about . It was separated from the North Shore of Long Island by the Harbor Hill Moraine, later approximately the route of Route 25. The modern Hempstead Turnpike approximately traces the separation of the plain from the South Shore of Long Island. The east-west extent was from somewhat west of the modern Queens, New York City border to slightly beyond the Suffolk County border.