The cemetery contains 3,512 interments from the Civil War, including the graves of 979 unknowns. It also has sections for veterans of the Spanish–American War, World War I, and other wars, along with graves of the veterans' spouses and children. The total number of interments exceeds 6,000.
Battlefield monuments, memorials, and markers are scattered throughout the cemetery, and its stone walls, iron fences and gates, burial and section markers, and brick sidewalk are listed as contributing structures within Gettysburg Battlefield Historic District.
The centerpiece of Gettysburg National Cemetery is Soldiers' National Monument (1869), a 60-foot-tall (18 m) granite monument designed by sculptor Randolph Rogers and architect George Keller. It is surrounded by concentric semicircles of graves, divided into 18 sections for Union states (1 each), a section for United States Regulars, and 3 sections for unknown soldiers.
Battlefield monuments within Gettysburg National Cemetery include those of the 1st United States Artillery Battery H, the 2nd Maine Battery, the 1st Massachusetts Battery (Cook's Battery), the 1st Minnesota Infantry, the 1st New Hampshire Light Battery, the 5th New York Independent Light Artillery, the 136th New York Volunteer Infantry, the 1st Ohio Battery H, the 55th Ohio Infantry, the 73rd Ohio Infantry, and the 75th Pennsylvania Infantry; and markers for the 1st Ohio Battery I and the 3rd Volunteer Brigade Artillery Reserve (Huntington's Brigade). Other monuments include the New York State Monument (1893), the Kentucky State Monument (1975), the Lincoln Address Monument (1912), the Friend to Friend Masonic Memorial (1994), the Major-General John F. Reynolds Statue (1872), and the Major-General Charles Collis Memorial (1906).