On the night of May 15, 1864, the 39th Illinois dug this earthwork as part of a quickly improvised Federal defensive line during the Bermuda Hundred Campaign. Unlike the carefully planned large Federal positions at Bermuda Hundred or the Confederate lines stretching from Drewry's Bluff, these defenses were hastily thrown up by individual companies along the front facing Confederate defenses. Such earthworks reflected how the accuracy and range of the rifled musket had transformed warfare by 1864, replacing earlier open-field Napoleonic tactics with a constant need to dig in whenever combat was expected. That night, along a 3 mile front, Federal regiments dug trenches, strung telegraph wire among tree stumps, or piled up logs and brush, while some had no time to prepare any defenses. After Confederate attacks on the Federal right and center on the morning of May 16, Major General Benjamin F. Butler ordered a retreat to Bermuda Hundred, but poor communication left the 39th Illinois stranded on the far left of the line. The regiment repelled three assaults at this position before being forced to withdraw south along the railroad.