This cannon ball was found embedded in a wall embankment in the Star Fort at Fort McHenry in the late 19th century as shown on the site base plan. Baltimore District Engineer, Major William P. Craighill uncovered the cannon ball while he was supervising a project for the U.S. Army Corps of Engineers at the site when it was still a military garrison.

The ball is typical of the solid cast iron balls made by foundries during the War of 1812. Liquid iron was poured into molds and then cooled and hardened in the shape of round balls. This was the type of ammunition used by the 1st Regiment, Maryland Volunteer Artillery who served at Fort McHenry. The soldiers strapped the ball to a wooden bowl called a sabot. The wooden bowl was attached to a bag filled with gun powder and then the entire assembly was inserted into the tube of a cannon. When the artillerymen lit the gun powder from the rear of the cannon, the exploded powder projected the cannon ball into the air. Attaching the ball to the sabot and bag of black powder was described as "fixed ammunition." This ammunition was placed in wooden chests that were stored in structures called Powder Magazines. Cannon balls were fired out of field artillery cannons that were placed and aimed towards the Patapsco River to protect the Star Fort from attack.

During the attack on Fort McHenry in 1814, a British bomb landed on the Powder Magazine located in the Star Fort. Fortunately, the bomb merely crashed through the building but did not explode. If it had exploded all the fixed ammunition stored in the Powder Magazine would have blown up and the entire Fort could have been destroyed!

Nearly one hundred years after the attack on Fort McHenry, the U.S. Army Corps of Engineers were conducting repairs to the Star Fort walls and battery areas. Major William Craighill found the cannon ball and presented it to the War Department for safekeeping as a museum object. Over 30,000 archeological artifacts have been found at Fort McHenry and are now in the park's museum collection. Often such items are recovered when work crews are digging trenches for utilities or performing restoration work on the site. Cannon balls, such as the one shown above, are routinely found at military sites, and they continue to provide a visual glimpse of our past military history.