The Sandy Hook Proving Ground was a military facility along the Atlantic coast of New Jersey established by the Secretary of War on August 7, 1874, to serve as the United States Army's first proving ground for the testing of ordnance and materiel. The facility was located at Sandy Hook, a narrow coastal spit of land, approximately 6 miles (9.7 km) in length and 0.5 miles (varying between 0.1 and 1 miles) wide, in Middletown Township in Monmouth County. The facility was operated in conjunction with the adjoining Fort Hancock.