Merrick Station lies on the Babylon Branch of the Long Island Rail Road. It was built in 1867 by the South Side Railroad of Long Island. The station was rebuild in 1885, 1902 and reached its current state in 1975.
The station has one 12-car-long high-level island platform that serves trains in both directions.
During morning rush hours, some westbound run express to Penn Station after Merrick. During the evening rush hours, Merrick is the first stop on some express trains originating at Penn Station en route to Wantagh Station.