Fort Miles — the fort built into a dune, for an attack that never came

Written August 2026 · Sources last checked 2 August 2026 · Corrections: hello@lewestown.com

Why a fort here at all

Cape Henlopen is the southern jaw of Delaware Bay. Everything bound for Wilmington and Philadelphia — the refineries, the shipyards, the industrial spine of the mid-Atlantic — has to pass between this cape and Cape May on the New Jersey side. Close that gap and you close the river. That single geographic fact explains why the cape has been fortified in one form or another through the Revolution, the War of 1812, the Civil War, and both world wars.

Fort Miles was the twentieth-century answer, and it was built for a specific fear: a German surface fleet standing off the coast and shelling shipping, or forcing the estuary outright. As the primary installation of the Harbor Defenses of the Delaware, it was designed to fight ships — not aircraft, not infantry. Funds were approved as early as 1934, but construction did not begin until 1938, and the fort grew fastest in the anxious months either side of America’s entry into the war.

The defences were not only gunnery. The fort operated a controlled underwater minefield across the mouth of the bay — mines that could be watched and detonated from shore rather than left to drift. That system left a long tail. In 2016, after Hurricane Hermine scoured the beach, park staff found one of those mines and its anchor still in the sand. It was recovered and archaeologically conserved rather than simply disposed of.

The towers everyone asks about

The concrete towers strung along the Delaware and southern New Jersey shore are the most visible thing Fort Miles left behind, and the most misread. They are fire-control towers. Coast artillery of this period aimed by triangulation: observers in widely separated towers each took a bearing on the same target, and a plotting room converted those bearings into a firing solution. The further apart the towers stood, the more accurate the fix — which is why they march away down the coast rather than clustering at the fort.

They look blind because the observation slits are narrow and set high, and they are unlovely because nothing about them was meant to be looked at. They were meant to look. One has been fitted with a staircase and opened to visitors inside Cape Henlopen State Park, which is the only way to grasp the scale of the sightlines they were built to command.

Named for a soldier who never saw it

The fort carries the name of Lieutenant General Nelson Appleton Miles (1839–1925), who fought in the Civil War, campaigned through the closing stages of the Indian Wars, commanded in the Spanish–American War, and served from 1895 to 1903 as the last Commanding General of the United States Army before that office became the Chief of Staff. He had been dead sixteen years when the fort was named for him.

There is a small disagreement about the date, and it is worth setting out rather than papering over. The published record gives the naming as 3 June 1941. Mrs. Brittingham’s original page at this address gives 8 August 1941. Worth noting: 8 August was Miles’s birthday — he was born on 8 August 1839 — which is exactly the sort of coincidence that can fasten a date to a story in retelling. We have not traced the War Department order that would settle it. Both dates are recorded here, and we are not in a position to declare either wrong.

What actually happened here

Almost nothing, and that was the point. No German surface fleet ever attempted the Delaware. The guns of Fort Miles fired in practice and never in anger against a warship — the ordinary fate of successful deterrent fortification, and a poor fit for the way we like war stories to end.

The bay was not quiet, though. The Atlantic seaboard in 1942 was a killing ground for U-boats working against coastal shipping, and the approaches Fort Miles watched were part of that war. At the very end of it the fort had its moment: German submarines surrendering in the western Atlantic were brought in past Cape Henlopen, and men who had spent years watching an empty horizon finally saw the enemy they had been built to stop — under escort, and flying a black flag.

From gun batteries to a state park

Coast artillery did not survive the war by much. By 1950 the coast-defence mission had passed to the Navy, fixed guns pointing at a horizon were obsolete, and the fort became surplus. The Army held on to portions, and in 1962 the Navy established Naval Facility Lewes here — a shore terminal for SOSUS, the Sound Surveillance System that listened for Soviet submarines across the Atlantic basin, replacing a facility at Cape May that had been damaged in a storm. NAVFAC Lewes was in commission from 1 May 1962 until 30 September 1981. Its headquarters building now houses the Biden Environmental Conference Center.

The land itself has a longer and stranger pedigree than the fort. In 1682 William Penn set the beaches of Cape Henlopen aside for “the usage of the citizens of Lewes and Sussex County” — among the first public lands declared anywhere in what became the United States. The cape was common ground for two and a half centuries before it was a fort, and it is common ground again: it formally became Cape Henlopen State Park in 1964 and now covers some 5,450 acres. Bunkers, batteries and towers sit inside it, which is why a walk here keeps running into concrete.

From the original page at this address

“On August 8, 1941, the concealed fortification on Cape Henlopen that had been under construction for several months received its name. The Harbor Entrance Control Post for Bay and River Delaware was christened ‘Fort Miles’ in honor of the late Lieutenant General Nelson Appleton Miles.”

Hazel D. Brittingham, “The Fort Was Named Miles”, Lewestown Publishers, 1997. © Copyright 1997 Hazel D. Brittingham. Short extract quoted for commentary; the full original is at the Internet Archive.