The Civil War - 150 Years Later - The Building Blocks of Armies

In this and subsequent special editions of Hooves, Heels and Wheels, the blog will take a look at the 150th anniversary of the events of the Civil War, and reflect on how they came about, and what implications they have for today ...

The Civil War

150 years ago This Week - The Armies Assemble and Grow

Spring, 1861

To Build an Army

150 years ago this spring, recruits flooded into the army camps throughout the North and South. For all of the men involved, it was a transformative experience and one of the most memorable times of their lives.

It was uncharted territory for Presidents Abraham Lincoln and Jefferson Davis as well, not to mention their War Departments (as the Department of Defense was called in those days). The sheer numbers of soldiers involved dwarfed any recruitment effort that the country had ever seen.

Up until 1861, the largest army ever seen in America was George Washington’s combined Franco-American force at Yorktown, at the end of the Revolutionary War. This force, impressive for its time, numbered about 20,000. The Union Army assembling in 1861 for the first thrust into Virginia would be half again as large- at 30,000. Confronting it would be a Confederate force of the same strength …and as the war continued, combat forces would only increase in size.


The Regiment – A Second Home


The basic building block of a Civil War army was a regiment of infantry commanded by a colonel. A regiment’s identification consisted of a number, and the state of recruitment, such as the “18th Pennsylvania”, the “33rd Virginia”, or the “10th New York”. Although unsophisticated, the name of the regiment, and at times it’s leader, were venerated by its members. A Civil War soldier took great pride in his regiment, and treated it like his home away from home. Indeed, in a very real sense, his regiment was just that.

Regiments were recruited locally, and a man would enlist with practically all the young men in his area at his side. Fathers served along side sons, brothers served together, and neighbors from down the street were often messmates and tent mates. Village and town doctors became regimental surgeons to the same young men they had delivered 20 years prior, and shopkeepers and professionals served next to their customers and clients.

The benefits to troop morale were enormous, and generals and politicians supported this system as a matter of course. Soldiers, it was believed, simply fought better when surrounded by family and friends. No soldier wanted to be known as the man who shirked his duty, or shrunk from combat in front of his neighbors, and a simple sense of duty to their hometown comrades would inspire soldiers to endure many a hardship in the months and years ahead.

This composition of regiments would, in the course of Civil War combat, show a very dark and horrifying side effect. A regiment could be sent to a particularly dangerous sector of a battlefield, and suffer dreadful casualties – resulting in the death, crippling or maiming of half the men from a given town in a single battle. Another battle months later could kill or wound most of the few that were left. The effect was less noticeable in large cities of course, but for many years after the Civil War, the map would be dotted with small “widow towns” that were populated mostly by women whose fathers, sons, husbands, brothers and sweethearts fell together at Shiloh’s Hornet’s Nest, Antietam’s Cornfield, Gettysburg’s Peach Orchard, or half a hundred other killing grounds.

Brigades, Divisions and Corps

For all the political differences seperating North and South, the two armies were grouped and organized the same way, so that the Union Army collecting in Washington DC was built almost identically to its southern counterpart. Civil War armies had three combat arms – Infantry, Cavalry, and Artillery. Infantry was by far the largest and most decisive branch.

Infantry regiments would be composed of ten companies of 100 men, each company commanded by a captain. Theoretically a regiment would thus have about 1000 officers and men, but hardly any Civil War regiment went into battle at full strength. From the day a regiment was formed soldiers fell sick, or became disabled in accidents. Some would even desert their units. Such attrition would start taking their toll on a regiment even before it saw its first battle.

Although a regiment could fight as an independent unit, it hardly ever did. Rather, regiments were grouped together in teams anywhere from two to six regiments (usually four or five). These regiment teams were called brigades, and they were commanded by brigadier (now called ‘one-star’) generals. Brigades would normally move and fight as one, with the brigadier general giving his commands to his several regimental colonels.

As the armies grew larger, brigades would be grouped into divisions, commanded by major generals. An infantry division could have anywhere from two to five brigades, and the brigades that formed them could have two to five regiments of various strengths, so the numbers of men in a division could fluctuate drastically from a small, under strength 5,400 to a large robust 16,000.

Later in the war, as armies became larger still, multiple divisions would be grouped into the largest formation of all, the infantry corps (pronounced "core") An army corps was a significant percentage of the Army, covered a large area on a battle map, and senior major generals commanded them. The spectacularly large battles of the Civil War would each involve over a hundred thousand combatants, and would involve entire corps charging into battle to clash with an enemy corps. The Confederates at Gettysburg had three corps of infantry, and the Union at Antietam had six corps. Since corps strength could fluctuate even more drastically then divisions or brigades, it’s pointless to compare “one Union Corps vs. one Confederate Corps” without knowing how many men were in fact in each.

Cavalry units were also grouped into regiments, but the companies that formed the regiments were known as troops. From there, like their infantry counterparts, cavalry units would be built into regiments, then brigades, then divisions. On some occasions, very large armies could have an entire corps of cavalry.

Artillery units were grouped into batteries – cannons working together as a team to gang up on the same target. A Union battery had six cannons; a Confederate battery usually unlimbered four guns.


Theoretically, a artillery piece was manned by eight men, while four men were nearby to handle the limber and caissons – wheeled vehicles that were attached to a cannon for transport – not to mention the horses. It took a team of six horses to move a cannon-and-limber rig, and six more to move the caisson-and-limber setup that provided ammunition.

Thus when a Union (Or Confederate) artillery battery rumbled onto the field, they unpacked six (or four) guns, twelve (or eight) limbers, six (or four) caissons, 72 (or 48) horses, and about 100 (or 70-80) men to make the whole unit work. Battlefields could quickly become crowded places.

Whether they were infantry, cavalry or atillery, the vast majority of soldiers on both sides were newcomers to warfare. America had not had a major conflict since the Mexican War (1846-1848), so an eighteen year old volunteer in 1861 had been five the last time the country had been at war. The officers were usually more experienced. Several middle age officers had been young men during the Mexican War, and a few officers had fought various Indian tribes over the years. By and large however the summer of 1861 involved one green army confronting another, led by a few generals of various experience.

For leadership in 1861, the South turned to their new hero, General Pierre Gustave Toutant Beauregard. Beauregard had commanded the Confederates at Fort Sumter, was thus the logical choice.




To be senior to Beauregard, President Davis and his military advisor, General Robert E. Lee, selected Joseph E. Johnston as the ranking field commander of the Confederate Army.


In Washington, the Union army had difficulty finding a handy general. With no victories yet, the North had no real heros, and most of the generals in the US Army were too old to take the field. None were more obviously past their prime then the General of the Armies himself, Winfield Scott. Tipping the scales at 300 pounds, and 75 years old, the venerable old general was no longer a battle leader. The next three generals in line were similarly handicaped by age and sickness.

With very few persons on the roster with any real credentials to their names, President Abraham Lincoln and General Scott tapped a Mexican War veteran, Irvin McDowell to command the growing army in Washington DC. McDowell recieved his promotion- and his big chance at the history books at the end of May 1861.


150 years ago this spring, two armies assembled and organized, as the nation - now two nations - waited with a mixture of excitement and fear for the War to begin in earnest.