Fort Duffield’s design reflects the urgency and ingenuity of late 1861. Built in just ten days by the
9th Michigan Infantry and 1st Wisconsin Infantry, the fort’s layout, cannon angles, interior spaces,
and winter adaptations reveal how soldiers transformed a rugged Kentucky ridge into a functioning
defensive position.

Louisville was one of the most heavily fortified cities in the Western Theater. By 1864, a complete
ring of forts, batteries, and rifle pits surrounded the city. Fort Duffield, though built earlier in
1861, served as a forward outpost guarding the river landing and turnpike feeding Louisville’s defenses.

Louisville Defences, 1864 — showing the ring of forts and batteries protecting the city.

Fort Duffield was engineered with ten distinct angles of fire, allowing its cannons to
sweep the turnpikes, river approaches, and ravines below. This defensive geometry dictated the fort’s
zig‑zag shape.

Angles of fire for the ten cannon positions — covering every approach to West Point.

The engineering diagram below shows how Fort Duffield’s earthworks were originally constructed in
November 1861. Soldiers cut earth from the ridge and carried it in blankets, baskets, and grain sacks.
They packed the soil into parapets reinforced with logs and brush, following U.S. Army field‑fortification
standards.

Engineering diagram showing Fort Duffield’s original 1861 construction layout.

The zig‑zag shape of the walls was intentional: each angle created a new field of fire for the fort’s
ten cannon positions. The outer ditch and sloped glacis slowed attackers and exposed them to fire.
Timber‑braced gun platforms allowed artillery to sweep the turnpike, river landing, and ravines below.

This top‑down diagram shows the interior layout of Fort Duffield. It highlights the open parade ground,
walkways, and movement corridors connecting the cannon platforms. This was the daily working space
inside the fort.