Irish Units in the American Civil War
There were roughly 185,000 Irish-American immigrants who fought on both sides of the American Civil War. Of that number all but about 40,000 were in the Union forces. (The large total does also not include descendants of earlier immigrants who may have still held some affinity to their Irish heritage.) The bulk of the immigrants served in largely Irish units, though the organizational placement of those Irish units in the Union and Confederate armies was considerably different.
Why separate Irish units? It helps to understand how the armies were formed but it is also impossible to ignore that there was a certain amount of distrust and discrimination against the Irish in the United States at the time the war broke out.
The Confederates, of course, had to start from scratch. Since they considered themselves a union of almost sovereign states, they turned to those states to raise military forces. As for the Union, Lincoln had only a small standing army at his disposal when it became obvious that the Southern states were going to secede and that war was inevitable. That army was further reduced in size by the resignation of officers and men who felt their primary loyalties lay with the Southern states they called home and accepted positions in the Confederate forces.
In 1861, Lincoln also lacked the authority to raise a federal army or to institute a draft. (The draft didn't come until 1863.) Rather, he had to call upon the States that remained loyal to the Union to raise units that would in turn support the cause of preserving the Union by swearing allegiance to one of the Union's armies, such as the Army of the Potomac.
States Raise Their Units
On both sides, states raised forces by recruiting for specific units. Each unit raised carried its state's name and was raised in the neighborhoods of large northern cities, or in the towns and rural communities across all of the States. Brothers, cousins, fathers, and uncles signed on together and went to battle side-by-side. Since the largely Catholic Irish were not completely trusted by their Protestant neighbors, particularly in the North, they generally joined separate units. These units, of company strength, were roughly 80-100 men, including about 65-80 privates. Many communities, of course, felt the price for this as the war progressed if the unit(s) they sent off suffered heavy casualties. (It was not unusual for individual units to experience 50 percent casualties in some Civil War battles.)
The Irish Brigade at Harrison's Landing, Virginia, 1862 Photo from the Library of Congress Civil War Photograph Collection
