Sandy Hook is a barrier spit located in Middletown Township, Monmouth County, New Jersey, in the United States. It sits at the north end of the Jersey Shore and measures approximately 6 miles (9.7 km) in length, with a width varying between 0.1 and 1.0 mile.
The geographical formation encloses the southern entrance of Lower New York Bay south of New York City. Its primary function is to protect the bay from the open waters of the Atlantic Ocean to the east.