Group 63 Interim Trail

The Group 63 Interim Trial is a 3.6 mile dirt road that loops around the former ammunition bunkers. Many of the bunkers are sealed and not open to visitors, however Bunker Group 63-1 is open.

Although often called "bunkers," arsenal workers and the military referred to them as "igloos.” Because the 60x20-foot structures were built of reinforced poured concrete, the pattern left on the walls by the cement forms gives the appearance of blocks piled on each other, as in an arctic igloo. Due to their highly volatile contents, the 392 igloos were built to withstand and contain an explosion. Because it would be costly to remove them, several are in use as seed storage for the native seedbeds that provide Midewin with much of it’s native plant stock.

In Bunker Group 63-1 visitors will see some of the many “bunkerglyphs” discovered in the 392 buildings. The graffiti found in the bunkers has provided archeologists, volunteers, and visitors a window into the people who once worked at the Joliet Army Ammunition Plant. Most of the annotated dates ranged from the 1940s up through the 1970s.

Although much of the graffiti was mundane, there was also some skilled artwork, professions of love and an occasional derogatory reference to an individual or the Army.

Names of workers, when they worked there, and where they hailed from were popular annotations. The more mundane graffiti, such as summing of numbers on the walls, may have been done by workers to see if the maximum pounds of explosives allowed per bunker had been reached. Various other stamp and stencil markings provide information on where the ammunitions were shipped.

At a Glance