This regiment organized at Fort Mitchell in the summer of 1861, and moved at once into Virginia. Joining the main army near Manassas, it was brigaded with the 21st Georgia, 21st North Carolina, and 16th Mississippi, under Gen. G. B. Crittenden of Kentucky; Gen I. R. Trimble succeeding Crittenden in December. When the army moved over to Yorktown, the Fifteenth remained on the Shenandoah, in Gen. T. J. Jackson's division. It was engaged with slight loss at Front Royal and Winchester, but lost 9 killed and 33 wounded, out of 425, at Cross Keys. Moving over to Richmond, in Jackson's flank movement on McClellan, it entered the first battle of Cold Harbor with 412 men, and lost 34 killed and 110 wounded. Five days after, it suffered lightly at Malvern Hill. On the march in Maryland, it was engaged at Hazel River and Manassas Junction with a loss of 6 killed and 22 wounded. A day or two later, the Fifteenth participated in the second and greater battle of Manassas, losing 21 killed and 91 wounded out of 440 men engaged. At Chantilly the regiment lost 4 killed and 14 wounded, and took part in the investment of Harper's Ferry, with trivial loss. At Sharpsburg, of 300 engaged, 9 were killed and 75 wounded. Under fire at Fredericksburg, the casualties were one killed and 34 wounded. The Fifteenth was then placed in a brigade under Gen. Law (with the Fourth, Forty-fourth, Forty-seventh, and Forty-eighth Alabama regiments), Longstreet's corps. At Suffolk it lost 4 killed and 18 wounded. It took part in the grand assault of Hood's division on Gettysburg, and within a few minutes lost 72 killed, 190 wounded, and 81 missing out of 644 men engaged. The Fifteenth suffered lightly at Battle Mountain, and, transferred to the West, bore its colors proudly at Chickamauga, where it lost 19 killed and 123 wounded, out of 425 engaged. In the fierce fights at Brown's Ferry and Lookout Valley, the regiment lost 15 killed and 40 wounded. Six killed and 21 wounded at Knoxville, and light casualties at Bean's Station, closed the operations of the regiment in Tennessee. It took 450 men in at the Wilderness and Spotsylvania, and lost 18 killed and 48 wounded. At Hanover Junction and the second Cold Harbor the loss was 6 killed and 16 wounded, and then the regiment took its place in the "last ditch" at Petersburg. At Deep Bottom a third of its 275 men present were killed or wounded, and at Fussell's Mill the loss was 13 killed and 90 wounded. The Fifteenth took part in the subsequent severe fighting, and surrendered at Appomattox 170 strong. Of 1633 on the rolls, over 260 fell in battle, 440 died in the service, and 231 were transferred or discharged.

Colonels - James Cantey of Russell; promoted. John F. Treutlen of Barbour; resigned. William C. Oates of Henry; wounded at Brown's Ferry. A. A. Lowther of Russell; wounded at Fussell's Mill.

Lieutenant Colonels - J. F. Treutlen; promoted. Isaac B. Feagan of Barbour; wounded at Gettysburg; retired.

Majors - J. W. L. Daniel of Barbour; resigned. A. A. Lowther; wounded at Wilderness; promoted.

Adjutants - Locke Weems of Russell; transferred to line. DeB. Waddell; transferred to line.

Russell - A. A. Lowther; promoted. Locke Weems; mortally wounded at Gaines' Mill. F. K. Shaaf.

Barbour - Isaac B. Feagan; promoted. R. A. Wright; wounded at second Manassas; retired. Noah B. Feagan.

Macon - Peter V. Guerry; killed at first Cold Harbor. J. H. Ellison; killed at Gettysburg; .... Guerry.

Barbour - .... Worthington; died in the sevice. B. A. Hill; killed at Fussell's Mill.

Dale - E. Brooks; resigned. W.A. Edwards; resigned. G. A. C. Mathews; wounded near Richmond; retired. .... Glover; killed at Petersburg.

Pike - B. F. Lewis; resigned. Geo. Y. Malone; wounded at first Cold Harbor; retired. DeKalb Williams.

Henry - W.C. Oates; promoted. Henry C. Brainard; killed at Gettysburg. John A. Oates; died of wounds received at Gettysburg. DeB. Waddell.

Barbour and Dale - W. N. Richardson; captured in east Tennessee. Benjamin Gardner; resigned.

Pike - Frank Park; killed at Knoxville. W. H. Strickland; wounded at Fussell's Mill.

Barbour - Henry C. Hart; transferred to department duty. W. J. Bethune; wounded at Gettysburg.

Pike (March 1862) - .... Hill; killed at Cross Keys. Lee Bryan; wounded at first Cold Harbor; retired. Jas. Hatcher.