The settlers gradually developed the island by building log and earthwork dikes to minimize storm damage and convert the marshes into good grazing meadows.

Hog Island supposedly got its name from the pigs which local residents left to roam free, as no fencing was needed.

In 1917, as part of the World War I effort, the U.S. government contracted American International Shipbuilding Corp. to build ships and a shipyard at Hog Island.

The city of Philadelphia bought Hog Island from the federal government in 1930 for $3 million but the Great Depression delayed work until 1937.

Domenic Vitiello, professor of Urban Studies at the University of Pennsylvania, asserts that Italians working on Hog Island in the old Navy Yard introduced the sandwich, by putting various meats, cheeses, and lettuce between two slices of bread.