With Johnston’s withdrawal from Kennesaw, the scene of war in Georgia shifted south to the vicinity of Atlanta. Approximately 8 miles northwest of the city itself ran the Chattahoochee River, the last major natural obstacle between Sherman’s army group and its major objective. The Chattahoochee ran southwest, in perfect alignment for Johnston to use it as a shield for Atlanta. But there was one problem: the river’s north bank dominated the south bank almost all along the line. This fact reduced its effectiveness as a defensive position, giving Federal artillery a good platform on the heights to support river crossings. (This geography is apparent to drivers entering Atlanta today via I-75; once passing the interchange with I-285, the freeway slopes down dramatically as it approaches the river, then across the bridge begins a gentle slope into the city.)
Johnston had been thinking of a fight along the river, and decided to use the heights himself and make a stand in the vicinity of Vinings, astride the road and railroad into Atlanta from the northeast (roughly the corridor of modern US 41 and I-75). For a month, a legion of slaves had dug six miles of strong earthworks, complete with abatis and gun emplacements. Six pontoon bridges connected the army with Atlanta. On July 4, 1864, the Army of Tennessee took up position in the so-called Chattahoochee River Line. Defending here shielded Atlanta, enticed Sherman into an attack, and also preserved the possibility of a counteroffensive. It also caught Sherman by surprise, who did not expect it.
Despite all this, Johnston’s decision to stand north of the Chattahoochee with virtually his entire army must be judged a mistake. Defeat north of the river would force his army back on six bridges, with great peril executing that crossing. The river at his back also constrained his ability to maneuver and redeploy against any Federal flanking marches. If Sherman flanked Johnston out of the works by crossing the river, Johnston would lose both the fortified and river lines and be flushed out into the open. In effect, Johnston limited his options to either standing passively or frontally counterattacking the Federals.
Sherman closed up to the line on July 5, and called off a planned attack after personally seeing the Chattahoochee River Line’s strength. He then spent several days resting his men and repairing the railroad. “From a hill behind Vining’s Station I could see the houses in Atlanta, nine miles distant, and the whole intervening valley of the Chattahoochee,” recalled Sherman.
On July 9, Sherman moved. Feigning to the west with McPherson’s forces, he made sure Thomas’ army kept Johnston occupied in front. Meanwhile Schofield’s army marched upstream, where they forced a crossing south of Roswell against Wheeler’s cavalry. Frustrated, Johnston withdrew southward July 12. The last natural shield before Atlanta had been thrust aside.
The final word on this operation goes to Sherman: “I have always thought Johnston neglected his opportunity there, for he had lain comparatively idle while we got control of both banks of the river above him.”