Work on Fort Duffield began in the fall of 1861 under the 9th Michigan Infantry Regiment commanded by Colonel William W. Duffield and the 37th Indiana Infantry Regiment commanded by Colonel George W. Hazzard, with the building of the work and garrison duty falling to the 9th Michigan, the first Michigan regiment to report for duty in the western theater. Other units known to have occupied the area included Lanphere’s Coldwater battery of Michigan, the 1st and 8th Ohio, the 1st Wisconsin, and the 16th and 28th Kentucky infantry regiments. This massive earthen fort was designed to stop cannonballs and was armed with cannon mounted on pedestals for easy turning at each of its ten angles, protecting against approaches from the many back roads coming in from the south rather than from the river. Its timber gates, trenches, cabins, and campsites for 1000 men were completed in one and one half months, and stone hearth and chimney ruins, along with many log cabin depressions, remain identifiable within the fort. The inexperienced troops who labored with pick-ax and shovel suffered from hard labor, exposure, and poor living conditions; many became sick, and 61 died and were buried on the hill west of the fort. Ordered by General William Techumseh Sherman to protect his and the Ohio River supply base at West Point and the city of Louisville via the Louisville-Nashville turnpike, this fortress was never challenged.