Why an Ammunition Magazine Had to Exist

Although no primary documents explicitly reference an ammunition magazine at Fort Duffield, the fort’s
ten 6‑pounder smoothbore cannon positions required a protected storage structure for black powder,
artillery rounds, friction primers, fuses, and rifle cartridges. U.S. Army engineering and ordnance
manuals of the Civil War era mandated that any fortified position with artillery maintain a secure,
dry, and protected magazine for ammunition.

Powder kegs, cannonballs, shells, and small‑arms cartridges could not be left exposed to moisture or
open flame. Even though the exact magazine has not been located archaeologically, its presence is
inferred from standard U.S. Army practice and the fort’s known armament. Reports indicate that
cannonballs were still present at Fort Duffield as late as 1895, further supporting the need for a
substantial ammunition storage facility.

Location and Strategic Placement

Civil War field manuals directed that powder magazines be placed on the safest interior side of a
fort—protected from enemy fire, distant from cooking fires, and situated on dry ground. This area of
Fort Duffield’s interior matches those requirements: sheltered by earthworks, close enough to the
cannon positions for rapid resupply, yet separated from daily camp activities that might introduce
sparks or open flame.

Based on terrain, access, and typical fort layouts of the period, this spot is the most likely
location for Fort Duffield’s ammunition magazine. The drawing above represents a historically
informed reconstruction of what such a structure would have looked like in 1861.

Construction and Design

Military engineering manuals describe a typical Civil War field magazine as a timber‑lined,
earth‑covered bunker, partially dug into a hillside. Heavy timbers formed the walls and roof, with
seams sealed by clay to keep out moisture. The entire structure was then buried under several feet of
packed earth to protect the powder from enemy fire and accidental explosions.

Ventilation was critical. Magazines used baffled ventilation openings—small, offset shafts that
allowed air to circulate without admitting sparks or direct light. Inside, powder kegs were stacked
on wooden racks, while cannonballs and other projectiles were stored separately to reduce risk.
Cartridges for rifles and small arms were kept in sealed crates to protect them from dampness.

Approximate Dimensions

• Length: 25–35 feet
• Width: 10–14 feet
• Interior Height: 7–8 feet
• Earth Cover: 3–6 feet of packed soil

A structure of this size could store an estimated 40–50 kegs of black powder and hundreds of
projectiles for the fort’s guns, along with cartridges for the infantry.

Interpreting the Drawing

The illustration shows an earth‑covered ammunition magazine dug into a hillside, with a timber‑framed
doorway and a small ventilation opening to the side. The door stands open, revealing the dark interior
where powder and ammunition would have been stored. A Union infantry soldier stands at the entrance,
resting one hand on the door frame—a reminder that such structures were guarded carefully due to the
danger and importance of the contents.

Though this specific magazine has not been found, the drawing represents a typical Civil War–era
ammunition storage shelter, consistent with U.S. Army regulations and the needs of a fortified
position on a strategic ridgeline like Fort Duffield.

Discover More

Scan the QR code on the nearby sign to explore the full history, engineering details, and
archaeological context of Fort Duffield’s defenses, including its inferred ammunition magazine and
the artillery that once commanded the approaches to Louisville.