Middle Island is a hamlet and census-designated place (CDP) in the Town of Brookhaven, Suffolk County, New York, United States. The population was 10,483 at the 2010 census. It is situated between the hamlets of Coram and Ridge, to the west and east, respectively, and Rocky Point and Yaphank to the north and south. The name derives from the fact that it lies approximately halfway between the eastern and western ends of Long Island as well as halfway between the northern and southern boundaries.

New York State Route 25 (NY 25) is an east–west state highway in downstate New York in the United States. The route extends along the central parts and North Shore of Long Island for just over 105 miles (169 km) from east midtown Manhattan in New York City to the Cross Sound Ferry terminal at Orient Point on the end of Long Island's North Fork. NY 25 is carried from Manhattan to Queens by way of the double-decked Queensboro Bridge over the East River.