Concrete Igloos

Sometimes referred to as concrete igloos, the remaining bunkers of the old Joliet Arsenal dot the landscape. With walls over 12 inches of solid concrete, these bunkers were used to store explosives produced at the arsenal. Approximately 400 feet apart, they were accessible by a network of railroad tracks within the base.

The tracks have since been removed, but miles of trails wind through the prairie, giving hikers and riders on horseback access to this unique park.

The Elwood Ordnance Plant and Kankakee Ordnance Works opened in the early stages of World War II, even before the U.S. joined the battle. The two plants combined in 1945 to create the Joliet Arsenal. During WWII, and up until the late 1970s, the plant produced artillery shells, mines, bombs and other munitions. At it's peak, the plant employed over 10,000 workers, and produced over 900 million shells and bombs, along with 450 million metric tons of TNT. These items and their components were safely stored inside the concrete bunkers.



In 1942, a powerful explosion rocked the Elwood plant, killing dozens of workers. The blast was felt as far away as Waukegan, IL over 60 miles away.

Today, 19,000 acres of the arsenal have been reclaimed to form the Midewin National Tallgrass Praire. Other lands were used for industrial parks and the Abraham Lincoln National Cemetery.