Shinnecock Inlet is the easternmost of five major inlets  connecting bays to the Atlantic Ocean through the narrow 100-mile-long Outer barrier that stretches from New York City to Southhampton, New York on the south shore of Long Island. It splits Westhampton Island from the peninsula extending from Southampton Village. The name comes from the Shinnecock Indian Nation.
Maintenance of the inlet has been controversial.
It saves boaters in the Hamptons several miles in access to the Atlantic Ocean. The inlet is almost directly lined up with the Shinnecock Canal between Shinnecock Bay and the Peconic Bay which allows a shortcut to the ocean for boaters on the north fork of Long Island.
Consequently management has been geared to keep the inlet dredged and open. However, the inlet has interrupted the flow of sand (which normally flows east to west) and consequently there has been major beach erosion on the west side of the inlet including the November 1992 Nor'easter that wiped out much of West Hampton Dunes, New York. The phenomenon is called longshore drift.
Efforts to prevent erosion with groynes have just pushed the problems further east resulting in serious beach erosion problems on Fire Island. West Hampton Dunes was incorporated in 1993 specifically to have legal standing in the skirmishes with Corps of Engineers regarding the practice. In 2010 the inlet was dredged and the sand deposited on the beach at Road K as part of the West of Shinnecock Inlet Interim Plan to replenish the sand.
The major inlets on the barrier beach are:
- State University of New York Description of the Issues
- USGS Page on 1992 Westhampton Nor'easter
- Google Satellite Image
- Press Release for 2010 dredging
- West of Shinnecock Inlet Interim Plan