After Confederate Lt. General Joseph E. Johnston's victory at Kennesaw Mountain, Union Lt. General William Tecumseh Sherman flanked the mountain and chased the Rebel army south of Marietta on July_2, 1864. Francis A. Shoup, the Confederate Chief of Artillery, approached Johnston with an idea - a fortification that could be used by a smaller force to hold a larger force at bay.
The line, built by impressed slave labor, consisted of earthen trenches with timber guards that protected the important Western and Atlantic Railroad bridge at Bolton and stretched from Mableton in the south to Smyrna in the north on mostly loam and dry loam soils. When Sherman first saw the fortification he described them as the "strongest field fortifications I ever saw."
When Sherman started the Atlanta Campaign Johnston ordered 100 men to guard the Western and Atlantic bridge over the Chattahoochee River at Bolton. General Mansfield Lovell was then dispatched to inspect the vicinity of the Bolton bridge and the pontoon bridge at Turner's Ferry to see if defenses coul be constructed.
As Joe Johnston withdrew from Kennesaw Mountain and nearby Marietta the Chattahoochee River was the largest natural boundary between his army and Atlanta and if "Cump" Sherman struck his army while crossing it could mean thousands of lives lost. Shoup's reinforced trench line would give Johnston a "last stand" position on the west bank of the Chattahoochee and the time he would need to safely cross the river.
The railroad bridge at Bolton was key to Johnston's withdrawal across the Chattahoochee. Throughout the month of June, 1864, various assignments went out for the construction of the works near Bolton, most notably to Lt. Col. Wilson Pressman, Chief Engineer of the Army of Tennessee on June_10, 1864. About that time Brigadier General Francis Asbury Shoup, chief of artillery and a graduate of West Point (1855), approached Johnston with an idea of building fortified trenches along the west bank of the Chattahoochee.
On June_19, 1864, work began on Shoup's plan for field works and Shoup arrived the next day. He found an existing line of trenches that he intended to expand and lengthen. The expansion consisted of adding series of earthen forts connected by trenches with stockades (palisades of vertically mounted logs sharpened on top) to further protect the infantry. Each fort was diamond-shaped and above grade with a parapet for sharpshooters. The trenches were broken about every 30-75 yards by artillery redans.
A second line was built extending along a ridge south from the depot at Smyrna. When the Confederates withdrew from the Kennesaw Mountain line on July 2, most moved to the forward Smyrna line, but that served for only two days as the forward defense. On July 5, 1864 the Smyrna Line was abandoned.
Johnston's vanguard began deploying on the river line on July 3, 1864. The line had fortifications from both the front and back, leading more than one Confederate officer to comment it was as if this was to be the site of the last stand of the Confederate Army in Atlanta. By July 5 Sherman deployed about half his fighting force in front of Johnston's River Line. Kenner Garrad was ordered to take Roswell Mill and the Roswell Covered Bridge over the Chattahoochee, while divisions from the XX Corps and the XXIII Corps began exploring for crossings to the north.
Army of the Ohio commander John Schofield secured the first crossing where Sope Creek joins the Chattahoochee. The following day Garrard's cavalry, wearing only weapons and cartridge boxes, secured a landing across the Chattahoochee River at Roswell. With the Chattahoochee breached, Johnston had little choice but to abandon the River Line.
The Civil War in Georgia Beginning with the Great Locomotive Chase and the battle of Chickamauga, to the Atlanta Campaign and the March to the Sea