Sandy Hook is a barrier spit in Middletown Township, Monmouth County, New Jersey, United States. The barrier spit, approximately 6 miles in length and varying from 0.1 to 1.0 mile wide, is located at the north end of the Jersey Shore. It encloses the southern entrance of Lower New York Bay south of New York City, protecting it from the open waters of the …Sandy Hook is a barrier spit in Middletown Township, Monmouth County, New Jersey, United States. The barrier spit, approximately 6 miles in length and varying from 0.1 to 1.0 mile wide, is located at the north end of the Jersey Shore. It encloses the southern entrance of Lower New York Bay south of New York City, protecting it from the open waters of the Atlantic Ocean to the east.