Despite the early optimism of both the Union and Confederacy, by summer 1862, it was increasingly evident that the Civil War would be both long and costly. It was also apparent that additional burial grounds would be needed to accommodate the growing number of Union soldiers who died from battle injuries and disease.
While New York City and its outskirts were outside the area of military conflict, numerous hospitals were set up here to care for wounded Union troops. Cypress Hills began as a zone of the Interior Military Cemetery and was located within the boundaries of the large and private Cypress Hills Cemetery in Brooklyn. Almost three acres were set aside for the burial of Civil War dead in what became known as Union Grounds. In 1870, the Cypress Hills Cemetery Corporation deeded the property to the United States for a consideration of $9,600. An inspection report of September 1870 indicates that 3,170 Union soldiers and 461 Confederate POWs were already buried there. Most of the interments came from military hospitals in the area. There were also a number of reinterments from cemeteries on Long Island Sound and in Rhode Island.
Prior to 1873, eligibility for burial in a national cemetery was restricted to U.S. soldiers who died as a result of injury or disease during the Civil War. In 1873, however, Congress approved legislation extending burial rights to honorably discharged soldiers, sailors and Marines who served during the war. To accommodate the growing number of burials requested at Cypress Hills, more than 15 acres were purchased in 1884. In addition, in 1941, a small tract within the old Cypress Hills Cemetery, known as the Mount of Victory Plot, was donated by the State of New York. Today the cemetery consists of three parcels totaling a little over 18 acres: the Union grounds, a larger area on Jamaica Avenue, and the Mount of Victory. Although Cypress Hills was established to honor Civil War veterans, its grounds include the graves of soldiers who fought in the American Revolution, Spanish-American War, Korean and Vietnam wars. Cypress Hills National Cemetery was listed on the National Register of Historic Places in 1997.