150 years ago this week: Federal armies are on the move in North Georgia. They quickly run into stiff Confederate resistance.

In February 1864, Gen. Joseph E. Johnston’s Army of Tennessee near Dalton had resisted elements of Maj. Gen. George Thomas’s Army of the Cumberland as they attempted to force the Confederates from the position they had occupied since November, when they had fallen back from Missionary Ridge outside Chattanooga.

On May 6 and 7, the defenders would face a greater test as Maj. Gen. William T. Sherman’s three armies comprising the Military Division of Mississippi moved in the direction of Tunnel Hill. The opening salvos of the Atlanta Campaign centered near the Western & Atlantic Railroad passage through the mountains, with both sides determined to hold fast. Skirmishing occurred for two days before the Confederate troops fell back to Rocky Face Ridge.

One of the Federal soldiers involved in the attempt to take Tunnel Hill — where the W&A passed through its namesake tunnel — wrote of how his regiment paid “our respects to them with artillery and musket. … It soon got too warm for the Johnnys.” The Confederates fell back, “and we took possession of the fortifications.”

Rocky Face Ridge seemed aptly named: The precipice towers above the surrounding countryside, and the rock cliffs made the position virtually impregnable. Three gaps passed through the range: Buzzard Roost or Mill Creek, Dug Gap, and Snake Creek Gap. Sherman had plans to exploit the third passage; he ordered an advance of the armies of Thomas and Major General John Schofield, while Maj. Gen. James McPherson would attempt to penetrate Snake Creek Gap and sever the W&A. (The Confederates relied on the railroad to supply them from the south, as the Federals did to supply them from the north.)

At first, things went as planned for McPherson. His men marched through the gap and had the rail line in sight and nearly in their grasp. But the Federal commander overestimated the number of Confederate troops manning the position in his front. Thinking he was outnumbered, he ordered his force to pull back into the gap.

McPherson told Sherman the evening of May 9 of his failed mission.

“The enemy have a strong position at Resaca,” McPherson explained. “They displayed considerable force, and opened on us with artillery. After skirmishing till nearly dark … I decided to withdraw the command.”

Part of the resistance McPherson observed included cavalry units arriving in the area. Earlier in the day, Johnston, fearing a movement through Snake Creek Gap, ordered his cavalry commander Maj. Gen. Joseph Wheeler to send troopers “toward Resaca to observe any movement. … Let them observe all gaps through which an enemy may pass across Rocky Face south of Dug Gap.”

Sherman wrote in his postwar memoirs of this missed opportunity: “Such an opportunity does not occur twice in a single life, but at the critical moment, McPherson seems to have been a little cautious.”

After the Snake Creek Gap action, a Kentucky soldier wrote, “Beautiful morning. With the light of day came the sound of the sharpshooters’ rifles, which have been continuously popping all day.” The Confederates had weathered one storm, but another, a force from Mother Nature, rolled into the area as the skies darkened and rain began to fall. The combatants would briefly wait out the storm before repositioning once again.

Michael K. Shaffer is a Civil War historian, author and lecturer. He can be contacted at: mkscdr11@gmail.com

For a list of Civil War 150th anniversary commemorative events in North Georgia, go to: http://bit.ly/1rToUhR and for prior Shaffer columns and other coverage, go to Civil War: 1864 in the AJC, http://www.ajc.com/s/opinion/