Shinnecock Inlet is the easternmost of six permanent inlets in the barrier island chain that follows Long Island's south shore. Shinnecock Inlet is located in eastern Long Island in Suffolk County, near the town of Southampton, and connects the Atlantic Ocean to Shinnecock Bay. The inlet was formed during the Great New England Hurricane of 21 September, 1938, when high waves and a storm surge overwashed the barrier.
The morphologic history of the inlet can be divided into three phases:
Since 1939, an oval-shaped ebb shoal has grown out into the Atlantic Ocean. The total volume of sand that accumulated in the shoal between 1938 and 1998 was 8,453,000 yd3 , representing an average growth rate of 14 1,000 yd3/year. In contrast, the flood shoal has lost sand since 1938, largely as a result of dredging the navigation channels in the back bay. After the jetties were built in 1952, the thalweg has been stable. The minimum cross-section, 1,600 m2 (17,000 ft2), occurs about 150 m north of the tip of the east jetty.