Fort Slocum

Fort Slocum
Company type	Military installation
Industry	Military
Founded	1867
Fate	Deactivated in 1965
Headquarters	New Rochelle, New York, United States
Area served	United States (East Coast)
Products	Military training, coastal defense, medical treatment

Adapted from the English Wikipedia article Fort Slocum, available under CC BY-SA 4.0Updated 7 August 2025

Fort Slocum, New York was a United States military installation located on Davids Island in the western part of Long Island Sound, within the boundaries of New Rochelle, New York. Operational from 1867 until 1965, it was named in honor of Major General Henry W. Slocum, a Union corps leader during the American Civil War. The post was instrumental in coastal defense, medical treatment, and military training throughout its active years.

Civil War

The military presence on Davids Island commenced in 1861 when the 3rd Regiment (63rd New York Infantry) of the Irish Brigade established Camp Carrigan there. In 1862, the U.S. Government leased the island for use by the Regular Army and founded De Camp General Hospital, named for Dr. Samuel G. I. de Camp, which treated thousands of wounded soldiers from Civil War battles. By the end of 1862, it had become the Army’s largest general hospital, accommodating over 2,100 patients.

Originally dedicated to caring for Union troops exclusively, De Camp Hospital expanded its capacity following the July 1863 Battle of Gettysburg to include hundreds of injured Confederate soldiers. Although a prison camp operated on Hart Island since 1865, Davids Island housed more than 2,500 Confederate prisoners of war during the conflict. Most prisoners recovered by October and were subsequently relocated to other camps. A ferry service connected the island with Neptune Island, which was managed by entrepreneur Simeon Leland.

Post Civil War

Following the Civil War, Congress approved the acquisition of Davids Island for continued military purposes, officially designating it as the Davids Island Military Reservation in 1867. The federal government maintained a dedicated ferry route to Neptune Island. In July 1878, Davids Island was designated as a primary depot for the U.S. Army General Recruiting Service, establishing its enduring function as a recruitment and training facility.

Late 19th century through 1916

During the 1880s, the Army significantly developed the installation by constructing over twenty brick structures that included officers' housing, barracks, mess halls, hospitals, and auxiliary buildings. In 1896, it was renamed Fort Slocum in tribute to Major General Henry W. Slocum. Following recommendations from the Endicott Board of Fortifications in 1885, Davids Island became integrated into New York Harbor’s coastal defense network.

From 1891 to 1904, several artillery batteries were erected on the island’s eastern section: Battery Practice featured older weaponry from the 1870s for training purposes; advanced Abbot Quad heavy mortar batteries Haskin and Overton housed sixteen breech-loading 12-inch mortars; and medium-range rifled gun batteries Fraser and Kinney were also installed. Battery Practice included a 15-inch smoothbore Rodman gun alongside two converted 8-inch rifles but was decommissioned in 1899, although the 15-inch gun remains present on site. Batteries Kinney and Fraser were armed with 6-inch and 5-inch artillery pieces respectively.

Battery Haskin was named after General Joseph A. Haskin; Battery Overton honored Captain Clough Overton; Battery Kinney commemorated Joseph Kinney; and Battery Fraser bore the name of Upton S. Fraser. With technological progress exemplified by dreadnought battleships and new defensive systems such as the Coast Defenses of Long Island Sound, these batteries became outdated by the early twentieth century. Fort Slocum was removed from New York’s artillery defense network in 1907 but retained its armaments throughout World War I. At this stage, Davids Island served as the East Coast assembly point for units deploying to America’s overseas territories.

World War I

After the United States entered World War I, Fort Slocum rapidly became one of the country’s most active recruit training centers, processing approximately 100,000 soldiers each year. It served as the primary examination hub for recruits from New York, New Jersey, Pennsylvania, and the New England region. From 1917 through 1919, more than 140,000 new soldiers passed through its facilities. The influx during Recruit Week in December 1917 was so substantial that additional accommodations had to be arranged in New Rochelle to handle the overflow.

Beginning in 1917, the fort’s artillery pieces were removed and reassigned. The 6-inch guns from Battery Kinney were transferred to Fort Tilden, while the 5-inch guns of Battery Fraser were likely readied for deployment on the Western Front, although no definitive records confirm their use in France. By 1919, Fort Slocum had been completely disarmed; its complement of sixteen mortars was taken away and potentially converted into railway artillery units.

Between the wars

A military downsizing in 1922 posed a threat to Fort Slocum’s continued operation, yet it remained active with multiple functions. The site accommodated a US Olympic Team, hosted a camp for the Civilian Conservation Corps, and operated the Army’s cooks’ and bakers’ school. Infrastructure enhancements included replacing the original 1884 water tower in 1929 and installing a modern sewage system. During the 1930s, most of the coastal defense batteries were demolished to make room for three new barracks collectively known as the Trivium.

World War II

On May 16, 1941, as tensions escalated in Europe, Fort Slocum became part of the New York Port of Embarkation, serving as a vital staging ground for troops deploying overseas. It provided training cadres for additional staging facilities in the Greater New York area such as Camp Kilmer and Camp Shanks. The fort was also home to the Atlantic Coast Transportation Officers' Training School, which transitioned civilians from transportation sectors into Army positions. As an essential element of the Army's Transportation Corps, established in mid-1942, Fort Slocum played a key role in managing large-scale overseas movement of personnel and equipment.

By early 1944, with troop shipments to Europe declining, Fort Slocum adopted a rotation system that sent non-combat personnel abroad while bringing battle-experienced soldiers back to the United States. These returning veterans underwent retraining at a "Provisional Training Center" designed to reintroduce them to domestic Army discipline and standards. During this time, in May 1944, Private Willie Lee Duckworth created the well-known "Sound off, one, two" military cadence. In November 1944, as transportation training activities diminished, Fort Slocum shifted its mission toward rehabilitating soldiers who had been court-martialed in Europe and sent back home.

Late 1940s

Following World War II, there was brief consideration of converting Fort Slocum into a nuclear research facility; however, Brookhaven National Laboratory was ultimately chosen for that purpose. Between 1946 and 1949, the fort served as Headquarters for the First Air Force and was redesignated Slocum Air Force Base in June 1949 before reverting to Army control in June 1950. From 1955 to 1960, Fort Slocum hosted part of the Nike Ajax air-defense missile battery NY-15. Missiles were stored on launch rails and within underground bunkers on nearby Hart Island, while radar and control installations were situated on Davids' Island. After five years of service, Nike Battery NY-15 was decommissioned in July 1960.

1950-1965

Between 1951 and 1962, Fort Slocum functioned as the location for the U.S. Army Chaplain School. During this period, it also accommodated the joint services Armed Forces Information School from 1951 to 1954. This institution evolved into the Army Information School, which was later restructured as the Defense Information School in 1964 before being transferred to Fort Benjamin Harrison, Indiana, and subsequently to Fort Meade, Maryland. The school specialized in educating military personnel in fields such as journalism, communication, broadcasting, public affairs, and photography. In 1965, following the deactivation of Fort Slocum, the information school was relocated to Fort Benjamin Harrison.

After closure

Fort Slocum officially ceased operations on November 30, 1965. In the decades that followed, its infrastructure fell into severe disrepair, complicating redevelopment initiatives on Davids Island. Beginning in 2004, Congress allocated funds to a Defense Department program aimed at clearing the remaining ruins and promoting community-oriented reuse of former military properties. By the summer of 2008, the city of New Rochelle undertook demolition of all existing buildings, including the landmark water tower, with intentions to transform the island into a public park.

"Sound off, one, two"

The well-known military cadence "Sound off, one, two" traces its origin to Fort Slocum in May 1944 and is attributed to Private Willie Lee Duckworth from Sandersville, Georgia.

Other uses of the name

The designation Fort Slocum also pertains to a Civil War fortification within the Defenses of Washington, D.C., named in honor of Colonel John S. Slocum from Rhode Island, who was killed at the First Battle of Bull Run. The Library of Congress possesses photographs labeled Officers, 4th U.S. Colored Infantry, Fort Slocum, April 1865, which most likely depict this Washington fort since that regiment never served north of Baltimore, Maryland.

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