From the Document: "Arlington National Cemetery (ANC) is a military cemetery administered by the Department of the Army. On June 15, 1864, the War Department appropriated the burial site as a military cemetery. Located in Arlington County, Virginia, the cemetery was created in 1864 during the Civil War from 200 acres of plantation land that once belonged to George Washington Parke Custis, step-grandson of the first U.S. President. Custis bequeathed his estate to his daughter who had married U.S. Army 2nd Lt. Robert E. Lee in 1831. At the start of the Civil War in 1861, the Custis Lee family fled the property. The Union Army then occupied and fortified the estate to help defend the nation's capital. In 1863, the Freedman's Village was established on the southern portion of the property to assist former slaves transitioning to freedom by providing shelter, medical care, education and training. The first military burial took place on May 13, 1864, for Private William Henry Christman, 20, a Union soldier from Pocono Lake, Pennsylvania. Two Unknown Union Soldiers were later interred on May 15, 1864, the first of nearly 5,000 Unknowns now resting in ANC. By the end of the Civil War, the grounds contained the graves of 6,000 Union soldiers. On March 3, 1883, the U.S. government purchased the property for $150,000 after years of legal wrangling with the Custis Lee family."
CRS In Focus, IF11362
Congressional Research Service: https://crsreports.congress.gov/