Fort Miles was a United States Army World War II installation located on Cape Henlopen near Lewes, Delaware.

The fort also operated a controlled underwater minefield to prevent ships entering the Delaware River estuary.

The Army continued to use portions and in 1962 the Navy established Naval Facility (NAVFAC) Lewes, a Sound Surveillance System (SOSUS) shore terminal there to replace the one at Cape May across the bay in New Jersey that was damaged in a storm.

The outbreak of war in Europe in September 1939 and the Fall of France in June 1940 greatly accelerated US defense planning and funding.

On 27 July 1940 the Army's Harbor Defense Board recommended the construction of 27 (eventually 38) 16-inch (406 mm) two-gun batteries to protect strategic points along the US coastline, to be casemated against air attack.

The United States declaration of war on Japan compelled the U.S. Army to continue to garrison the fort with the 261st Coast Artillery Battalion, who days before were slated to leave.

Fourteen vessels, including USS Jacob Jones, a U.S. Navy destroyer, were sunk off the coast of New Jersey during the first six months of 1942.

Each of these had two 6-inch (152 mm) guns on high-angle shielded barbette carriages, with a concrete-and-earth bunker for ammunition and fire control.

Five such towers still exist within the current boundaries of Cape Henlopen State Park, including one (#7) that has visitor access.

With a significantly reduced threat from enemy surface forces, in March 1944 the first of several drawdowns at Fort Miles commenced.

Due to the late date of its completion, Battery 519 was never formally named and was only designated by its Army Corps of Engineers construction number.

Over time, more land was transferred to the state park until Fort Miles ceased operation as a military MWR facility altogether in 1991, as part of the Base Realignment and Closure Commission (BRAC) process.

Fort Miles, consisting of approximately 96 acres, was transferred to the State of Delaware only for public park or recreational purposes.

[22][23][24][25] Since the SOSUS program was not officially declassified until 1991, the actual operations of NAVFAC Lewes remained classified for the duration of the facility's existence.

[26] The headquarters building that also contained some quarters, eating and recreation facilities, became a Naval Reserve Center until all land was returned to the state in 1996.

A married housing complex became facilities for the University of Delaware College of Earth, Ocean and Environmental Sciences.

[27] Battery Smith originally housed the two 16-inch (406 mm) guns and is in use by Cape Henlopen State Park for storage.

These events are designed to give the public a demonstration of military life at Fort Miles when it was still in operation.

Reenactors at the fort portray the 261st Coast Artillery Battalion and Detachment A, 1252nd Service Command Support Unit (Quartermaster Corps).