The Aberdeen Proving Ground Main Post Cemetery is located in Aberdeen, Maryland. The cemetery is part of the oldest active Military proving ground, Aberdeen Proving Ground, and was established on October 20, 1917 - six months after the U.S. entered World War I. The cemetery occupies just over a ½ acre of land. This cemetery does not possess a columbarium; all graves are in-ground gravesites. Although the cemetery is only open to subsequent interments, the interment average is one interment per year.