As initially organized, the brigade had the following regiments:[5] Throughout 1862, Major General William S. Rosecrans and his Army of the Cumberland were driven to distraction by Confederate cavalry and irregulars.

As a result of the failure, Rosecrans and his subordinates revisited the experiment with wagons from the October events and realized the solution to their problems was the early role of dragoons as mounted infantrymen.

Due to this speed of deployment, the unit earned the nickname, "The Lightning Brigade", and it would prove the validity of its conversion in the campaign in the Western theater.

[31] By the middle of the latter month, the brigade's soldiers had realized the advantages the breech-loading repeating rifle held over the muzzleloader, and they exuded confidence in themselves, their leaders, their new tactics, and their treasured new weapons.

In fact, to preclude them being mistaken for cavalry, Wilder had the brigade remove the yellow cloth tapes from the outseam of the standard riding trousers which had been issued from the quartermasters.

[46] Colonel James Connolly, commander of the 123rd Illinois, wrote: As soon as the enemy opened on us with their artillery we dismounted and formed line of battle on a hill just at the south entrance to the "Gap," and our battery of light artillery was opened on them, a courier was dispatched to the rear to hurry up reinforcements, our horses were sent back some distance out of the way of bursting shells, our regiment was assigned to support the battery, the other three regiments were properly disposed, and not a moment too soon, for these preparations were scarcely completed when the enemy opened on us a terrific fire of shot and shell from five different points, and their masses of infantry, with flags flying, moved out of the woods on our right in splendid style; there were three or four times our number already in sight and still others came pouring out of the woods beyond.

Our regiment lay on the hill side in mud and water, the rain pouring down in torrents, while each shell screamed so close to us as to make it seem that the next would tear us to pieces.

[47]After a long day of combat at 1900, the brigade's morale was uplifted by the arrival of a fresh battery at the gallop, which meant the XIV Corps were close behind.

The corps commander, General Thomas, shook Wilder's hand and told him, "You have saved the lives of a thousand men by your gallant conduct today.

[49] On June 25, Bate and Johnson renewed their attempts to drive the Union men out of Hoover's Gap but failed against the Lightning Brigade now with its parent division and corps.

With his corps commanders unnerved by the Lightning Brigade's raid, at 3 p.m. on June 30, Bragg issued orders for a nighttime withdrawal from fortifications in Tullahoma across the Elk River.

Rosecrans tried to continue his war of maneuver and get around Bragg's flank to threaten his rear and force him to abandon Chattanooga vice taking it in a pitched battle.

[63] The 92nd and its companions quickly worked their way towards the Tennessee River, through Dunlap, reaching Poe's Tavern,[64][note 3] to the northeast of Chattanoogas Ridge on August 20.

The steep slopes of the Cumberland Plateau and Walden's Ridge were difficult terrain, and there was a dearth of forage, but the two brigades still made good time in their advance.

The 92nd and its brigade mates covered southern side, from city to Sale Creek, and Minty's men from there north to the mouth of the Hiawassee River.

Rosecrans had ordered the brigade to shell Chattanooga from the north bank of the Tennessee River to divert attention away from the flanking columns sent southwest of the city.

The men in the brigade opposite the city found some Confederate soldiers on the north bank, ignorant of the Union force approaching with the 123d Illinois capturing forty prisoners and a ferry.

At Harrison's Landing, the 92nd and 98th Illinois found no meaningful forces save a single gun in a small fort on the south bank that was quickly destroyed by the accompanying section of Lilly's Battery.

Next, opposite the city, Wilder brought forward Captain Lilly with his remaining two sections and set them up on high ground about one half mile from the river.

[67] The deception operation included the 92nd and its compatriots faking boat construction by hammering, sawing, and tossing bits of lumber into the river at Harrison's Landing so that it would float downstream to Chattanooga.

On the morning of September 5, the rest of the Wilder and Minty were themselves tricked when Bragg's forces faked preparations to cross the river to the north side to attack.

[66] Wilder did not pursue the retreating enemy because that was a cavalry role, but he did pass on reports from local inhabitants to Rosecrans which deceived him into believing Bragg was fleeing in chaos to Dalton or Rome, Georgia.

[75][76] (September 11–12, 1863) As Rosecrans moved his forces south and west, the heavily wooded and hilly terrain soon had 60 miles of separation between his three making mutual support nearly impossible.

Bragg attacked General James S. Negley's isolated division of the Union XIV Corps, commanded by George H. Thomas, before Rosecrans could concentrate the rest of his army across Chickamauga Creek near Davis' Cross Roads.

[92][91][93] Through the morning to midday of 19 September, the Lightning Brigade held its position as a reserve near Viniard farm slightly uphill and behind the main line.

[98] Hood's Corps advanced so close to Rosecrans's new headquarters at the Glenn Cabin leading to a significant risk of a Federal rout in this part of the line.

[97] At dawn, on September 20, Rosecrans personally ordered the brigade to take position west across Dry Valley Road on the crest of the east slope of Missionary Ridge at the right end of XX Corps and to report to Maj. Gen. McCook.

The 39th Indiana had been detached Willich's 1st Brigade from Johnson's Second Division of McCook's XX Corps and was acting as an independent mounted infantry army-level asset.

In the time that Wilder took to arrange a small detachment to escort him back to safety, the opportunity for a successful attack was lost and he ordered his men to withdraw to the west.

As they fell back, they collected the details from the 92nd Illinois and set a screening line across Dyer Road as it passed through the gap from the hill to the mountain with the Vittetoe house in its center.