Assault on Pigeon Hill, Kennesaw Mountain. On June 27, 1864, three brigades of 5,500 soldiers from Ohio, Indiana and Illinois charged Pigeon Hill. One Union brigade overran the Confederate rifle pits near this location while the other two other brigades crossed Old Mountain Road. The attack ran into felled trees and other Confederate-built obstacles on Pigeon Hill. As the Federals struggled over the obstructions and rough terrain, the entrenched Southerners opened fire with musketry and cannon. Some Confederates on Little Kennesaw even heaved boulders. The Union troops sought cover and the assault crumbled. By noon the Union forces had withdraw to Old Mountain Road. They returned to their lines. Federal casualties were 850, Confederate 250.