Fort Lilly was a cigar-shaped Union redoubt on the prominent high ground known as Fort Hill, where White and Black Union soldiers watched traffic along the paved Columbia Turnpike, which followed the current US 31, and the National & Decatur Railroad. It served as the anchor for defenses protecting the busy transportation hub of Pulaski. U.S. Army units such as the 9th Indiana Cavalry and the 110th and 111th U.S. Colored Troops served there. The U.S. Colored Troops at Fort Lilly were primarily recruited from Black men who had been enslaved in Giles County and Limestone County, Ala. They defended and repaired the critical railways and roadway infrastructure that kept supplies flowing to Union armies, serving alongside U.S. Colored Troops units from across Tennessee and other White U.S. Army units. The fort was named in honor of Capt. Eli Lilly of the 9th Indiana Cavalry, who was captured in 1864, returned home, and formed the Eli Lilly Pharmaceutical Corporation.