Massapequa is a hamlet and census-designated place in the Town of Oyster Bay in Nassau County, on the South Shore of Long Island, in New York, United States. It is considered the anchor community of the Greater Massapequa area. The population of the CDP was 21,685 at the time of the 2010 census. The Greater Massapequa area, which includes the nearby CDPs of North Massapequa and East Massapequa, as well as the incorporated village of Massapequa Park, has a combined population of over 75,000.