From 1863 to 1865, Rock Island Arsenal was home to one of many Civil War prison camps. As with other camps in the North, the camp at Rock Island was plagued with disease and illness that took the lives of both prisoners and guards. Most of the dead were afflicted with smallpox or dysentery. Confederate prisoners were buried in the old Confederate cemetery that has since been moved. Union guards were buried separately from the Confederate dead at the old guard cemetery near the arsenal's old housing area.

When the arsenal was in its development phase, it was decided that the location of both cemeteries conflicted with the location of future construction. Brigadier General Thomas Rodman, commander of RIA, opted to move the cemeteries to the upper end of the island to their present day location. The Confederate Cemetery included the dead from the original cemetery. The new National Cemetery included dead from the old guard cemetery, as well as dead from the original post cemetery situated near Fort Armstrong.

The older post cemetery was dated to 1836, and was situated near the crossroads of Fort Armstrong Avenue and Beck Road outside the present Rock Island Gate.

In addition to remains from the old guard and post cemeteries, soldiers who had served during the Civil War and had been buried in other local cemeteries were moved to the National Cemetery on Rock Island Arsenal.

No markers remain today of either the old post cemetery, or the original guard cemetery.