Saddle Rock Grist Mill is a historic grist mill building located in Saddle Rock, a village in the town of North Hempstead in Nassau County, New York. It is a 2+1⁄2-story gambrel-roofed structure. Adjacent is a stream-fed millpond that is supplemented by tidal water impounded by the dam. It dates to the 18th century and is the only extant tidal grist mill on Long Island. The building underwent restoration in the 1950s and was operated as a local history museum, but is now closed.