BLDGBLOG: Hog Island

BLDGBLOG:
"Hog Island was a shipbuilding yard – in fact, we read, it was "the largest shipyard in the world" during WWI.

The yard covered 846 acres and comprised 250 buildings. It had 80 miles of railroad track; 3,000,000 feet of underground wiring; a hospital; YMCA, hotel, cafeteria, trade school, 12 service restaurants and 5 mess halls. Twenty locomotives, 465 freight cars and 165 motor trucks hauled material within the yard. Hog Island's telephone traffic was equivalent to that of a city of 140,000 inhabitants.

And though Hog Island is now barely known outside of war historical circles, it was a true industrial behemoth:

There never before had been conceived or executed a plan for the fabrication of ships on such an enormous scale. Every steel fabricating plant in America, 88 of them in all, from Montreal to Kansas City, funneled steel plate into Hog Island and machinery and gear from hundreds of manufacturing plants all over the country poured into the mammoth assembly plant.

It was "a sizable piece of land – about a thousand acres – between Philadelphia and Chester, south of what was known then as League island," but it was also something of a manmade artifact, an artificial terrain.
Partially constructed from dredged fill in a "glorified bog," the industrialized earthworks were then turned – as you can see in the image, above – into a kind of machine-island, built to order."

I wonder what the legal status of this island was?