General Corps Information
In the Regimental Histories section of this website, you will find which Corps each Regiment was assigned to throughout the War. This section is being offered to help you understand how each Corps spent its' tenure in the American Civil War and will give you some general background useful in understanding the Corps organization.
Corps badges were first used by Kearny's Division, who wore a diamond shaped piece of flannel, in 1862 and were first ordered into general use in the Spring of 1863. The Army of the Potomac immediately adopted the use of badges, but armies in the West did not start using them until 1864, and then only occasionally. Some corps did not use badges at all. The badges used were various shapes and cut out of flannel, about one and one-half inches across, and subsequently attached to the soldier's hat. Those Corps which adopted the badges used different colors for each division: red for the first division, white for the second and blue for the third. The 6th, 9th and 20th Corps adopted green for their 4th division badges, the 15th Corps used yellow for its' 4th division and certain corps used multicolor badges for their headquarter and artillery elements.
In general, the various corps were organized of three divisions, with each division containing three brigades and each brigade made up of five regiments. This made a total of 45 regiments of infantry per corps, to which nine batteries of light artillery were added. However, this structure was fluid during the war in the sense that, at times, a corps may consist of four divisions, a division may consist of four brigades or a brigade may consist of eight or nine regiments. This was normally caused by attrition and to keep the corps at reasonable fighting strength, additional regiments were added. These situations were not the norm and most often proved to be temporary.
In 1863, the cavalry were organized into a corps by themselves; prior to that time, each corps was accompanied by a brigade of cavalry regiments.
Batteries of light artillery, usually organized in brigades of about 5 batteries each, were attached to each corps. In addition to the normal complement, the Army of the Potomac had an artillery reserve that consisted of five brigades - 21 batteries total. This Artillery Corps of the Army of the Potomac was commanded by General Henry J. Hunt.
Prior to the implementation of the corps organization, the Union armies consisted of divisions numbered in the order of their formation. The Western armies continued this type of organization until December of 1862 when they instituted the corps organization that was retained during the remainder of the war.
The information listed for each Corps is being taken from "Regimental Losses in the American Civil War (1861-1865)" by William F. Fox.
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This page last updated 01/25/09