The brigade gained the sobriquet “Horn Brigade” while under the command of August Willich,^[1] a former Prussian Army officer who favored using bugle calls to signal movements.^[2][3] It was also known as the Dutch Brigade because of the ethnic makeup of the brigade (mainly the 32nd Indiana) and the brigade commander.^[1][4] Later, it also became known as the “Iron Brigade of the Army of the Cumberland” following its actions on September 20, 1863, when it drove back an entire Confederate division during the Battle of Chickamauga.^[5][6]

The brigade that would later become known as the Horn Brigade originally consisted of the 15th Ohio,^[7] 49th Ohio, 32nd Indiana, 39th Indiana and Battery A, 1st Ohio Light Artillery.^[8] These units were later joined by the 89th Illinois, 25th Illinois, 35th Illinois, 68th Indiana, 8th Kansas, 15th Wisconsin, and 51st Indiana.

The brigade was known by the following designations: Johnson's Brigade, McCook's Command, to November 1861. 6th Brigade, Army of the Ohio, to December 1861. 6th Brigade, 2nd Division, Army of the Ohio, to September 1862.^[9] 6th Brigade, 2nd Division, I Corps, Army of the Ohio, to November 1862. 1st Brigade, 2nd Division, Right Wing, XIV Corps, Army of the Cumberland, to January 1863.^[10] 1st Brigade, 2nd Division, XX Corps, Army of the Cumberland, to October 1863.^[11] 1st Brigade, 3rd Division, IV Corps, to August 1865.

The brigade was further distinguished by a tactic invented by August Willich known as “advance firing,” in which the regiments were organized into four ranks (rather than two), with one rank moving forward, firing, and reloading as it was replaced with the rank farthest to the rear.^[12] This tactic was used by the 49th Ohio to great effect at the Battle of Liberty Gap during the Tullahoma Campaign and again by the brigade at the Battle of Chickamauga.^[6]

At the Battle of Missionary Ridge, the brigade led the charge against the Confederate lines against orders and was among the first to reach the top of the ridge.^[13]

• Richard W. Johnson
• William H. Gibson
• August Willich
• Charles T. Hotchkiss
• Abel D. Streight^[4]

• Daniel, Larry J. (2006). Days of Glory: the Army of the Cumberland 1861-1865. Baton Rouge, LA: Louisiana State University Press. pp. 333, 335. Retrieved 28 March 2018.
• Hunt, Robert E (2010). The Good Men Who Won the War: Army of the Cumberland Veterans and Emancipation Memory (pdf) (1st ed.). Tuscaloosa, AL: The University of Alabama Press. pp. 26–28, 37, 60, 66. ISBN 9780817383527. OCLC 929313559. Retrieved October 10, 2014.
• Prokopowicz, Gerald J (2001). All for the Regiment: The Army of the Ohio, 1861–1862 (pdf) (1st ed.). Chapel Hill, NC: University of North Carolina Press. pp. 1–15. ISBN 9781469620305. OCLC 1100952343. Retrieved October 10, 2014.
• Van Horne, Thomas B. (1875). The Army of the Cumberland: Its Organizations, Campaigns, and Battles (pdf). Vol. I (1st ed.). Cincinnati, OH: Robert Clarke & Co. pp. 64, 66, 113–118, 222–235, 260–281, 379, 415–425. OCLC 694011616. Retrieved October 10, 2014.
• Cist, Henry Martyn (1882). The Army of the Cumberland. Campaigns of the Civil War. Vol. 7 (1st ed.). New York, NY: C. Scribner's Sons. pp. 14, 18, 193–229. OCLC 558140877. Retrieved 28 March 2022.
• SLPL Genealogy, German Americans in the Civil War, St. Louis Public Library, archived from the original on August 14, 2020
• Mann, Richard F (2010). The Buckeye Vanguard: the 49th Ohio Veteran Volunteer Infantry (pdf) (1st ed.). Milford, OH: Little Miami Publishing. pp. 57, 58. ISBN 9781932250824. OCLC 1280767026. Retrieved August 18, 2021.
• Niles, E.W. (December 6, 1888). "Fighting Them Over: CAMPAIGN IN TEXAS-Willich's Dutch Brigade on the March" (PDF). The National Tribune. Vol. V, no. 18. Washington, DC. p. 4.
• U.S. War Department (1889). Operations in Kentucky, Middle and East Tennessee, North Alabama, and Southwest Virginia. January 21 – August 10, 1863. – Reports. The War of the Rebellion: A Compilation of the Official Records of the Union and Confederate Armies. Vol. XXIII-XXXV-I. Washington, DC: U.S. Government Printing Office. OCLC 857196196. Retrieved March 13, 2022.
• U.S. War Department (1899). Operations in Kentucky, Southwest Virginia, Tennessee, Mississippi, North Alabama, and North Georgia. August 11-October 19, 1863. – Part I Reports. The War of the Rebellion: A Compilation of the Official Records of the Union and Confederate Armies. Vol. XXX-XLII-I. Washington, DC: U.S. Government Printing Office. OCLC 857196196. Retrieved March 13, 2022.
• U.S. War Department (1899). Operations in Kentucky, Southwest Virginia, Tennessee, Mississippi, North Alabama, and North Georgia. October 20-December 31, 1863 – Part I Reports and Union Correspondence. The War of the Rebellion: A Compilation of the Official Records of the Union and Confederate Armies. Vol. XXXI-XLIII-I. Washington, DC: U.S. Government Printing Office. OCLC 857196196. Retrieved March 13, 2022.
• Otto, John Henry; Gould, David & Kennedy, James B (2004). Memoirs of a Dutch Mudsill: The "War Memories" of John Henry Otto, Captain, Company D, 21st Regiment, Wisconsin Volunteer Infantry (pdf). Kent, OH: Kent State University Press. p. 74. ISBN 9781612777924. OCLC 982451698. Retrieved November 30, 2017.
• Reyburn, Philip J. (2012). Clear the Track: A History of the Eighty-Ninth Illinois Volunteer Infantry, The Railroad Regiment (pdf) (1st ed.). Bloomington, IN: AuthorHouse. p. 368. ISBN 9781477254141. OCLC 1031454756. Retrieved November 30, 2017.
• Taft, W.F. (1887). ""About Willich's Bugles"" (PDF). National Tribune.