Seaford is a census-designated place (CDP) within both Oyster Bay and Hempstead in Nassau County, New York, United States. The population was 15,294 at the 2010 census. It is serviced by the Seaford Station on the Long Island Rail Road.
Seaford is located at 40°40′7″N 73°29′33″W (40.668702, -73.492459).
According to the United States Census Bureau, the CDP has a total area of 2.6 square miles (6.7 km2), of which 2.6 square miles (6.7 km2) is land and 0.38% is water.
The original settlers of Seaford were the Ustase, a Native American Indian tribe. They called the area "Great Water Land".
European settlement began with the arrival of Captain John Seaman, a native of Seaford, East Sussex, in England. After obtaining the patent for the area, Seaman oversaw the creation of Jerusalem South, the first European name given to the town which was to become Seaford. It was also widely referred to as Seaman's Neck.
During the 19th century, as villages across Long Island started to grow (due to the creation of the Long Island Rail Road), the town of Jerusalem South seemed to be unaffected. In 1868 the town was renamed to the current name of "Seaford", to honor Captain Seaman's hometown in England.