He identified an island that he called "Pip Ash" as an ideal site for the defense of the prize of American commerce and culture.

In 1820, seeking to resolve questions surrounding the ownership of the island, Secretary of War John C. Calhoun requested a legal opinion from Attorney General William Wirt.

Wirt's conclusion, based on a report by George Read, Jr. and former Attorney General Caesar A. Rodney was that the state of Delaware had the valid claim to the island, and so New Jersey could not have properly deeded it to Gale.

A fortification further downriver would also provide protection for other vital port cities such as Chester, Marcus Hook, Wilmington, and New Castle.

Completion of the project was delayed years past the proposed date due to uneven settling, improper pile placement and the island's marshy nature.

After conflicting opinions from two different circuit courts, President James K. Polk suggested an arbitrator resolve the disagreement, and Secretary of War William Marcy and Humphrey agreed.

[22] Because of the star fort's failed foundation, Totten and Sanders decided to evaluate the weight resistance before moving forward with construction.

Initially, the stone for the scarp wall was gneiss imported from long prized quarries around Port Deposit, Maryland (on the east bank of the Susquehanna River, north of the Chesapeake Bay)[23] In 1852, Major Sanders reported the gneiss was too hard for his stone masons and cutters to shape, slowing the progress of construction.

Due to the threat of high-tide waters, efforts were directed toward repairing the dike and adjacent seawall, slowing progress on the stonework.

These bricks were used in construction of underground cisterns, casemates, powder magazines, soldier barracks, officer quarters, bread ovens and the fort's breast high wall.

[25] On July 29, 1858, Major Sanders died on the island due to "complications of carbunculous boils"; Lt. William Craighill replaced him until Maj. John Newton was able to assume the role of supervising engineer.

Construction languished until the end of the Civil War; the garrison's focus was centered on mounting cannon inside the fort.

In 1862 and 1863, two separate phases of construction took place, building a "barracks for enlisted prisoners of war" that was known as the "bull pen," said Pvt.

"These Barracks [sic] were common wooden sheds, affording accommodation for about ten thousand persons," wrote Lt. Francis W. Dawson, a Confederate POW captured in August 1862.

[34] Many of the Confederate prisoners and Union guards who died at the fort are buried in the nearby Finn's Point National Cemetery in Pennsville, New Jersey.

[35] By 1863, enlisted men and junior officers (mostly lieutenants and captains) of the prison population were living in the wooden barracks on the northwest side of the island.

"We went into dinner about three o'clock, which consisted of three hardtack, a small piece of meat (about three bites) and a pint tin cup of bean soup.

"[39] High-ranking Confederate officers and some political prisoners were housed in former laundress quarters and open-bay barrack rooms inside the fort.

"[45] On August 20, 1864, six hundred Confederate States Army officers boarded the Crescent bound for Morris Island off the coast of South Carolina, "for the purpose I believe of being placed under the fire of the Confederate batteries in retaliation for an equal number of Federal officers who have been placed in the city of Charleston, and are said to be exposed to the shelling of their own guns.

"[47] "After long delay - all being ready - the guards took their places, and the command was given to march through the sally-port, to the west end of the "bull-pen"," according to Reverend Isaac Handy.

We have had nothing like it since [October 1878] and a strong whirlwind with it, sweeping every thing before it, pulling trees out of the ground and carrying parts of the hospital all over the island and out on the river," wrote Ordnance Sergeant James Maxwell.

Instead of many guns concentrated in a traditional thick-walled masonry structure, the Endicott batteries are spread out over a wide area, concealed behind concrete parapets flush with the surrounding terrain.

[3] The parade ground was excavated and thousands of piles were steam driven, to support a foundation for a concrete three-gun battery as a way to modernize the defenses protecting ports along the Delaware River.

The new Endicott structure was a three-story reinforced concrete emplacement, which was built from 1894 to 1900 to support three 12-inch breech-loading rifled guns on disappearing carriages.

It had two 4.7-inch 40 caliber guns purchased from the United Kingdom; at that point few of the Endicott batteries were complete and it was feared the Spanish fleet would bombard the US east coast.

[62] In March 1919, soldiers began the process of mothballing the old fort, removing everything except items pertaining to the three 12-inch guns of Battery Torbert, according to Pvt.

The 4.7-inch guns of Battery Dodd were sent to San Francisco for use on Army troop transports; they were returned to Fort Delaware in 1919 but were soon removed from service and used as war memorials.

[61][64] Following the attack on Pearl Harbor, the island was garrisoned by a detachment of soldiers from Battery C, 261st Coast Artillery Battalion, a unit from the Delaware Army National Guard.

The United States Army Corps of Engineers erected a 3,500-foot-long seawall during the Winter of 2005-2006 which now protects the historical fort site and a migratory bird rookery, considered to be the largest such habitat north of Florida.

The Sci Fi Channel investigation series Ghost Hunters Academy recorded an episode, which aired June 23, 2010.