Franklin Square is a hamlet and census-designated place (CDP) in the Town of Hempstead in Nassau County, on Long Island, New York, United States. The population was 30,903 at the time of the 2020 census.
The area was originally known as Trimming Square and then as Washington Square.
What is now Franklin Square was near the center of the Hempstead Plains, and used as grazing land, and later farmland, by the first white settlers. The southern portion included oak and dogwood forests.
In late 1643, Robert Fordham and John Carman made a treaty with members of the Massapequak, Mericoke, Matinecock and Rockaway tribes to buy roughly 100 square miles upon which they intended to start a new settlement. They purchased this tract, including much of what are now the towns of Hempstead and North Hempstead.
In 1790, George Washington passed through the town while touring Long Island. He wrote in his diary that the area was "entirely treeless