Summary of the Lightning Brigade
With a potent combination of rapid-firing Spencer rifles, aggressive and determined leadership, and unlimited confidence in themselves, the soldiers of Colonel John T. Wilder’s mounted Lightning Brigade—so christened during the summer of 1863—solidified a reputation in the savage battle of Chickamauga as one of the Union Army’s hardest fighting and most effective combat organizations.
Quick Facts About the Lightning Brigade
- Also Known As: The Lightning Brigade, led by John T. Wilder, was also called “Wilson’s Brigade” and “the Hatchet Brigade.”
- Start Date: William S. Rosecrans authorized the formation of the Lightning Brigade on February 16th, 1863.
- End Date: The Lightning Brigade was dissolved on October 23, 1863, when General Ulysses S. Grant reorganized the army.
- Part of: The Lightning Brigade was part of the Fourteenth Army Corps of the United States Army.
Beginning of the Lightning Brigade
Rosecrans Placed in Command of 14th Army Corps
On October 24, 1862, the U.S. War Department issued General Orders, No. 168 announcing the creation of the Department of the Cumberland “by direction of the President.” The order placed Major General William S. Rosecrans in command of the new department and its troops, designated the Fourteenth Army Corps (informally known as the Army of the Cumberland).
Battle of Stones River
On December 26, Rosecrans left Nashville with roughly 44,000 men, prepared to engage Confederate General Bragg and his Army of Tennessee. Bragg and about 38,000 soldiers were encamped at Murfreesboro, Tennessee.
The two armies engaged from December 31, 1862, through January 2, 1863, at the Battle of Stones River (also known as the First Battle of Murfreesboro). Following the hard-fought Union victory, Bragg withdrew to Tullahoma, Tennessee.
Rosecrans Requests Calvary
As Rosecrans planned his pursuit of the Rebel army, Confederate cavalry commanded by General John Hunt Morgan harassed the Union rear and threatened their supply lines. Desperate to stop Morgan’s raids, Rosecrans wrote to General-in-Chief Henry W. Halleck on January 14, 1863:
I must have cavalry or mounted infantry. I could mount infantry had I horses and saddles…with mounted infantry I can drive the rebel cavalry to the wall and keep the roads open in my rear Will you authorize the purchase of saddles and horses for mounting, when, requisite, 5000 or more infantry?
Rosecrans Authorizes Formation of the Lightning Brigade
When the War Department proved unable to supply the horses Rosecrans needed, he issued Special Field Order Number 44 (Department of the Cumberland) on February 16th, 1863, stating:
Brig Gen. J. J. Reynolds, commanding Fifth Division, Fourteenth Army Corps, is authorized to mount the Second Brigade (Wilder’s) of his command.
Rosecrans and Wilder agreed that the horses needed to mount the infantry brigade would be confiscated from “loyal Rebel citizens” from the surrounding Tennessee counties. By mid-April, the entire brigade was mounted.
Regiments in the Lightning Brigade
From the time of its inception in 1863 until the end of the Civil War in 1865, numerous units served with Wilder’s Brigade, some as detachments on a temporary basis. However, the core units of the brigade comprised the following four infantry regiments and one artillery battery:
17th Indiana Mounted Infantry Regiment
The 17th Indiana Volunteer Infantry Regiment (later the 17th Indiana Mounted Infantry Regiment). This unit was organized at Indianapolis, Indiana, on May 3, 1861, and mustered into service on June 12th, 1861, with Colonel Milo S. Hascall commanding. The regiment served in the District of the Kanawha, Cheat Mountain District in Western Virginia during 1861. On March 2, 1862, Wilder became the regiment’s colonel after Hascall became a general. Before joining Wilder’s Brigade, the regiment functioned as a traditional unit with the Army of the Ohio and the Army of the Cumberland in Kentucky and Tennessee during 1862 and 1863. The unit mustered out of service on August 8, 1865. During its service with the Volunteer Army, the regiment suffered 237 fatalities: three officers and ninety enlisted men killed or mortally wounded, and one officer and 143 enlisted men by disease.
72nd Indiana Mounted Infantry Regiment
The 72nd Indiana Volunteer Infantry Regiment (later the 72nd Indiana Mounted Infantry Regiment). This unit was organized on July 7, 1862, at Lafayette, Indiana, and mustered into service on August 16, 1862, with Colonel Abram O. Miller commanding. Before joining Wilder’s Brigade, the regiment functioned as a traditional infantry unit with the Army of the Ohio and the Army of the Cumberland in Kentucky and Tennessee during 1862 and 1863. The unit mustered out of service on June 26, 1865. During its service with the Volunteer Army, the regiment suffered 160 fatalities: two officers and twenty-six enlisted men killed and mortally wounded, and two officers and 130 enlisted men by disease.
92nd Illinois Volunteer Mounted Infantry Regiment
The 92nd Illinois Volunteer Infantry Regiment (later the 92nd Illinois Volunteer Mounted Infantry Regiment). This unit was organized in Rockford, Illinois, and mustered into service on September 4, 1862, with Colonel Smith D. Atkins commanding. Before joining Wilder’s Brigade, the regiment functioned as a traditional infantry unit with the Army of Kentucky and the Army of the Cumberland in Kentucky and Tennessee during 1862 and 1863. The regiment joined Wilder’s Brigade on July 10, 1863, and was mounted and armed by mid-August. The unit mustered out of service on June 21, 1865. During its service with the Volunteer Army, the regiment suffered 181 fatalities: one officer and fifty-one enlisted men killed and mortally wounded, and two officers and 127 enlisted men by disease.
98th Illinois Volunteer Mounted Infantry Regiment
The 98th Illinois Volunteer Infantry Regiment (later the 98th Illinois Volunteer Mounted Infantry Regiment). This unit was organized in Centralia, Illinois, and mustered into service on September 3, 1862, with Colonel John J. Funkhouser commanding. Before joining Wilder’s Brigade, the regiment functioned as a traditional infantry unit with the Army of the Ohio and the Army of the Cumberland in Kentucky and Tennessee during 1862 and 1863. The unit mustered out of service on June 27, 1865. During its service with the Volunteer Army, the regiment suffered 171 fatalities; thirty enlisted men were killed and mortally wounded, and five officers and 136 enlisted men by disease.
123rd Illinois Volunteer Mounted Infantry Regiment
The 123rd Illinois Volunteer Infantry Regiment (later the 123rd Illinois Volunteer Mounted Infantry Regiment). This unit was organized in Mattoon, Illinois, and mustered into service on September 6, 1862, with Colonel James Monroe commanding. Before joining Wilder’s Brigade, the regiment functioned as a traditional infantry unit with the Army of the Ohio and the Army of the Cumberland in Kentucky and Tennessee during 1862 and 1863. The unit mustered out of service on June 27, 1865. During its service with the Volunteer Army, the regiment suffered 219 fatalities: three officers and eighty-two enlisted men killed and mortally wounded, and one officer and 133 enlisted men by disease.
18th Indiana Battery
The 18th Indiana Battery was an artillery unit of about 150 men organized at Indianapolis in the summer of 1862 and mustered into federal service on August 24, 1862, with Captain Eli Lilly commanding. Before joining Wilder’s Brigade, the regiment served with the Army of the Ohio and the Army of the Cumberland in Kentucky and Tennessee during 1862 and 1863. The unit mustered out of service on June 23, 1865. During its service with the Volunteer Army, the battery suffered forty-three fatalities: one officer and eleven enlisted men killed or mortally wounded, and thirty-one enlisted men by disease.
Fighting Tactics of Wilder’s Lighting Brigade
Although the brigade traveled on horses, Wilder and his men viewed themselves as infantrymen rather than cavalrymen. Reportedly, one of their first acts upon receiving their new uniforms was to remove the yellow piping that would have identified them as a cavalry unit. Still, their status as mounted infantry required the men to assume the duties and responsibilities of a cavalry trooper. Many of them had to learn to ride and they all had to care for their mounts.
Much like the air cavalry units that were rapidly transported by helicopter to hot zones during the Vietnam War in the 20th Century, Wilder’s men used their mounts to deploy more quickly than traditional infantrymen who traveled by foot. Upon encountering their enemy, they dismounted and employed infantry tactics.
The Lightning Brigade and the Spencer Repeating Rifle
While Wilder was training his mounted brigade, Christopher Miner Spencer arrived at General Rosecrans’s headquarters to demonstrate a repeating rifle he had manufactured and was trying to sell to the army. Unlike the standard-issue breech-loaded muskets that a skilled soldier could load and fire a maximum of three times per minute, Spencer’s lever-action repeating rifle could quickly fire seven shots before needing to be reloaded. In the hands of skilled soldiers, the rifle could deliver up to twenty rounds per minute.
Wilder was so impressed by Spencer’s rifle that he canvassed his men and they agreed to adopt the new weapon. Unfortunately, army officials were unwilling to purchase repeating rifles because of concerns about soldiers wasting ammunition. Refusing to be denied the new weapon, Wilder bypassed the War Department and personally ordered enough rifles from Spencer to arm his brigade. To pay for the weapons, Wilder mortgaged his business and home to secure a bank loan, and each of his men co-signed promissory notes to cover the price of their individual rifles. Later in the year, after the rifles proved highly effective, the army reversed its position and covered the cost.
Campaigns and Battles of the Lightning Brigade
Tullahoma Campaign and Battle of Hoover’s Gap
In late June 1863, Rosecrans resumed his pursuit of Braxton Bragg’s Army of Tennessee. Bragg’s forces were encamped at Tullahoma, Tennessee, about twenty-six miles southeast of Rosecrans’s winter quarters at Murfreesboro, Tennessee.
On June 24, Rosecrans ordered Major General George H. Thomas and his 14th Corps to strike the mountain gaps in the middle of Bragg’s line. Thomas tasked Wilder with leading the initial assault on Hoover’s Gap, a four-mile-long pass through a range of hills that run westward from the Cumberland mountains.
Setting out at dawn on the 24th, during a steady rain that continued throughout the day, Wilder’s mounted infantry moved toward Hoover’s Gap ahead of Thomas’s main force. When Wilder’s men neared Hoover’s Gap, they were nearly nine miles ahead of the bulk of Thomas’s corps. At about noon, they engaged Colonel J. Russell Butler’s 3rd Kentucky Regiment, the lone Confederate force defending the pass through the mountains. Advancing farther than expected, Wilder’s 1,500 soldiers quickly dislodged the surprised Rebels and took possession of the gap. Wilder then ordered his men to prepare for the counterattack he expected.
As Butler’s men retreated, they encountered Confederate Brigadier General William B. Bate’s brigade. Upon learning of Butler’s withdrawal, Bate moved to regain possession of the gap. Three separate counterattacks during the afternoon proved unsuccessful. The Confederate breechloaders were no match for the firepower of the Spencers. By the time Rebel reinforcements arrived to support Bate’s attempt to regain the valley, Thomas’s 14th Corps arrived, and the fighting ended at about 7 p.m.
When Thomas met with Wilder, he gushed “You have saved the lives of a thousand men by your gallant conduct today. I didn’t expect to get this Gap for three days.” Thomas christened Wilder’s command as the “Lightning Brigade.”
Chickamauga Campaign and Battle of Chickamauga
Following the Union victory at the Battle of Hoover’s Gap, Confederate General Bragg’s Army of Tennessee retreated to Chattanooga, Tennessee, with Rosecrans’s Army of the Cumberland in pursuit. Early in September 1863, Rosecrans used Wilder’s brigade to deceive Bragg into believing that Rosecrans intended to cross the Tennessee River north of Chattanooga. Instead, Rosecrans divided his forces and crossed the river at three other locations, forcing Bragg to abandon Chattanooga. Rosecrans occupied the city on September 8, but rather than regrouping and securing the city as he had done at Murfreesboro, he pursued Bragg’s army into Georgia.
During the second week of September, Wilder’s brigade probed Confederate lines in northern Georgia and skirmished with Rebel cavalry near Ringgold, Georgia.
In mid-September, Rosecrans realized that rather than being in full retreat, Bragg intended to attack the divided Union forces in northern Georgia. On September 17, Rosecrans ordered Wilder’s Lightning Brigade and Colonel Robert Minty’s cavalry brigade to hold back over 8,000 advancing Rebels at several bridges and fords as they attempted to cross West Chickamauga Creek. The two brigades were all that stood in the way of Bragg’s effort to cut off the Union army from Chattanooga. For over five hours, the two Union brigades held back the surging Rebels before they forced their way across the creek. Wilder’s men fell back three miles and formed a defensive line. Armed with their Spencer repeating rifles, the Lightning Brigade halted two furious onslaughts from a much larger force before the Confederates abandoned their advance around 10 p.m.
Although Bragg punished the Army of the Cumberland for the next two days and forced Rosecrans to retreat to Chattanooga, Wilder’s Lightning Brigade and Minty’s cavalry had bought precious time for Rosecrans to reorganize his forces and prevented what could have been a much more devastating Union defeat at the Battle of Chattanooga. Rosecrans later observed:
“His [Wilder’s] command merits the thanks of the country for his noble stand at the crossing at Chickamauga.”
During the remainder of the Battle of Chickamauga (September 19–20) the Lightning Brigade was held in reserve and deployed to various hot spots to thwart Rebel advances and enable the Army of the Cumberland to retreat to Chattanooga in an orderly fashion.
End of the Lightning Brigade
Following his victory at the Battle of Chickamauga, General Bragg bottled up Rosecrans’ forces within Chattanooga, severed his supply lines, and began shelling the Federals. Union officials responded to the Confederate siege by sending 15,000 troops commanded by Major General Joseph Hooker and 20,000 troops commanded by Major General William T. Sherman to Chattanooga. More significantly, on October 16, 1863, the War Department issued General Orders, No. 337 creating the Military Division of the Mississippi, and placing Grant in charge of all Union armies in the western theater. Grant quickly relieved Rosecrans of his command and placed Major General George Thomas in charge of the Army of the Cumberland. When Grant arrived at Chattanooga on October 23, he reorganized the Union forces there, including Wilder’s brigade.
The reordering resulted in the Lightning Brigade being dissolved. The 75th Indiana, 92nd Illinois, and 123rd Illinois regiments and the 18th Indiana battery were transferred to the 3rd Brigade of the 2nd Division of the Cavalry Corps. The 98th Illinois and the 17th Indiana were assigned to the 2nd Brigade of the 2nd Division of the Cavalry Corps. Wilder was later brevetted to brigadier general and served during the Atlanta Campaign, but recurring bouts of illness forced his retirement from the military on October 5, 1864.
Significance of the Lightning Brigade
Wilder’s Lightning Brigade was just one of many mounted infantry units organized by both sides during the Civil War. Their successes during the Tullahoma and Chickamauga campaigns, however, have made them the most acclaimed unit. The brigade’s use of horses to quickly get them engaged with the enemy using infantry tactics served as a model for motorized infantry units used in later wars.
Cavalry Tactics at Chickamauga
This video from the National Park Service explains how Union cavalry, including the Lightning Brigade, used their weapons during the battle.