At the turn of the century, Fort Columbus and Governors Island began to draw the attention of President Theodore Roosevelt's Secretary of War, Elihu Root, a former New York City lawyer.
Root sought to enhance the island army post to better serve the army's needs, to fend off efforts by the City of New York to close the post and reclaim the island as a city park and a rarely stated need to provide a quick means of federal protection of Wall Street, the Customs House and Sub-Treasury in Lower Manhattan.
Root instigated the expansion of the island from its original 60 acres to 172 acres with landfill from the newly constructed New York City Subway and dredge from New York Harbor.
Root also commissioned the New York architectural firm of McKim, Mead and White to develop a master plan for the island which would demolish all the existing buildings on the island except for the three original fortifications on the island and a newly constructed chapel.
The retention of the fortifications indicated Root's interest in retaining the historical structures, as some of the army decision makers he supervised were trying to accomplish their demolition.
In one of his departing acts as Secretary of War in February 1904, Root restored the original name of Fort Jay to the fortification and to the army post that had evolved around it.

A 1930s WPA project was the complete conversion of the barracks in Fort Jay to family housing.
Each company barracks was transformed into four townhouse-style apartments that served junior officers as family housing.
As a further concession to the automobile, eight two-car garages were constructed inside the fort behind the barracks to serve the fort's residents.

During World War II Fort Jay was the headquarters of First Army in the early part of the war, and later the Eastern Defense Command (EDC), responsible for all Army units and defense coordination in the northeastern United States, and in the east coast states from Maine through Florida.
These were primarily coast defense, antiaircraft, and fighter assets.
US Army forces in Newfoundland and, from April 1942, Bermuda were also included in the EDC.
At the turn of the century, Fort Columbus and Governors Island began to draw the attention of President Theodore Roosevelt's Secretary of War, Elihu Root, a former New York City lawyer. Root sought to enhance the island army post to better serve the army's needs, to fend off efforts by the City of New York to close the post and reclaim the island as a city park and a rarely stated need to provide a quick means of federal protection of Wall Street, the Customs House and Sub-Treasury in Lower Manhattan. Root instigated the expansion of the island from its original 60 acres to 172 acres with landfill from the newly constructed New York City Subway and dredge from New York Harbor. Root also commissioned the New York architectural firm of McKim, Mead and White to develop a master plan for the island which would demolish all the existing buildings on the island except for the three original fortifications on the island and a newly constructed chapel. The retention of the fortifications indicated Root's interest in retaining the historical structures, as some of the army decision makers he supervised were trying to accomplish their demolition. In one of his departing acts as Secretary of War in February 1904, Root restored the original name of Fort Jay to the fortification and to the army post that had evolved around it.
A 1930s WPA project was the complete conversion of the barracks in Fort Jay to family housing. Each company barracks was transformed into four townhouse-style apartments that served junior officers as family housing. As a further concession to the automobile, eight two-car garages were constructed inside the fort behind the barracks to serve the fort's residents.
During World War II Fort Jay was the headquarters of First Army in the early part of the war, and later the Eastern Defense Command (EDC), responsible for all Army units and defense coordination in the northeastern United States, and in the east coast states from Maine through Florida. These were primarily coast defense, antiaircraft, and fighter assets. US Army forces in Newfoundland and, from April 1942, Bermuda were also included in the EDC.
Fort Jay