Greenvale is a hamlet and census-designated place (CDP) in Nassau County, New York on the North Shore of Long Island. As of the United States 2010 Census, the CDP population was 1,094. It is part of both the Roslyn and North Shore School Districts.
Located between Roslyn and Brookville, Greenvale is known as the Long Island Rail Road stop for the C.W. Post Campus of Long Island University and the New York Institute of Technology. The school is located to the east in Brookville, though using the Greenvale postal code. Until 1866 the community was originally known as "Cedar Swamp."
Greenvale is the site of the historic Roslyn East Gate Toll House, a toll house for the former North Hempstead Turnpike that has been on the National Register of Historic Places since August 16, 1977.
Greenvale is located at 40°48′47″N 73°37′32″W (40.813187, -73.625618).
According to the United States Census Bureau, the CDP has a total area of 0.3 square miles (0.78 km2), all land.
It is located in the Town Of North Hempstead.
As of the census of 2000, there were 2,231 people, 362 households, and 254 families residing in the CDP. The population density was 8,674.4 per square mile (3,313.1/km²). There were 372 housing units at an average density of 1,446.4/sq mi (552.4/km²).