Many cemeteries have monuments or markers denoting military service. My distant cousin that I mentioned recently, Paul Davis (Gilbert) has a marker on his grave. This is one of the common ones that make mention of the conflict served in, and they often serve as a flag holder.
posting. It honors those who served in the Grand Army of the Republic, as well as both world wars, Spanish American war, Korean and Vietnam wars.
The flag holder markers also serve the extra purpose of helping to find the graves. Since my great-great Grandfather's stone is flush to the surface of the ground, it frequently gets covered by leaves and grass. This marker helped me locate the stone, several times.