Infantry in the American Civil War

The Infantry in the American Civil War comprised foot-soldiers who fought primarily with small arms, and they carried the brunt of the fighting on battlefields across the United States. As the Civil War progressed, battlefield tactics soon changed in response to the new form of warfare being waged in America. The use of military balloons, rifled muskets, repeating rifles, and fortified entrenchments contributed to the death of many men. Generals and other officers, many professionally trained in tactics from the Napoleonic Wars, were often slow to develop changes in tactics in response.

Outbreak of war
At the start of the Civil War, the entire United States Army consisted of some 16,000 men of all branches, with infantry representing the vast majority of this total. Some of these infantrymen had seen considerable combat experience in the Mexican-American War, as well as in the West in various encounters, including the Utah War and several campaigns against Indians. However, the majority spent their time on garrison or fatigue duty. In general, the majority of the infantry officers were graduates of military schools such as the United States Military Academy.

In some cases, individual states, such as New York, had previously organized formal militia infantry regiments, originally to fight Indians in many cases, but by 1861, they existed mostly for social camaraderie and parades. These organizations were more prevalent in the South, where hundreds of small local militia companies existed.

With the secession of eleven Southern states by early 1861 following the election of President Abraham Lincoln, tens of thousands of Southern men flocked to hastily organized companies, which were soon formed into regiments, brigades, and small armies, forming the genesis of the Confederate States Army. Lincoln responded by issuing a call for 75,000 volunteers, and later even more, to put down the rebellion, and the Northern states responded. The resulting forces came to be known as the Volunteer Army (even though they were paid), versus the Regular Army. Infantry comprised over 80% of the manpower in these forces.

Organization
The typical infantry regiment of the early Civil War consisted of 10 companies (each with exactly 100 men, according to Hardee's 1855 manual, and led by a captain, with associated lieutenants). Field officers normally included a colonel (commanding), lieutenant colonel, and at least one major. With attrition from disease, battle casualties, and transfers, by the mid-war, most regiments averaged 300-400 men. Volunteer regiments were paid by the individual states, and officers at first were normally elected by popular vote, or were appointed by the state governors (particularly the colonels, who were often the men who had raised and organized the regiment). As the war progressed, the War Department and superior officers began selecting regimental leaders, and the regimental officers normally selected the NCOs (non-commissioned officers) based on performance and merit, although the individual states retained considerable influence in the selection of the regimental officers.

Often, and always, according to Hardee's 1855 manual, large regiments were broken into two or more battalions, with the lieutenant colonel and major(s) in charge of each battalion. The regiment may have also been divided into two wings, the left and right, for instructional purposes, only. The regimental commander exercised overall tactical control over these officers and usually relied on couriers and staff to deliver and receive messages and orders. Normally positioned in the center of the regiment in battle formation was the color guard, typically five to eight men assigned to carry and protect the regimental and/or national colors, led by a color sergeant. Most Union regiments carried both banners; the typical Confederate regiment simply had a national standard.

Individual regiments (usually three to five, although the number varied) were organized and grouped into a larger body (a brigade) which soon became the main structure for battlefield maneuvers. Generally, the brigade was commanded by a brigadier general or senior colonel, when merit was clearly evident in that colonel and a Brigadier was not available. Two to four brigades typically comprised a division, which in theory was commanded by a major general, but theory was often not put into practical application, especially when an officer exhibited exceptional merit or the division was smaller and trusted to a more junior officer. Several divisions would constitute a corps, and multiple corps together made up an army, often commanded by a lieutenant general or full general in the Confederate forces, and by a major general in the Union forces.

Below is charted the average make-up of the infantry for both sides.

Tactics
Commands were typically issued via voice, (rarely) drum (infantry only), or bugle call. Soldiers were drilled in infantry tactics, usually based upon a manual written before the war by West Point professor William J. Hardee (Rifle and Light Infantry Tactics: for the Instruction, Exercise and Manoeuver of Riflemen and Light Infantry, published in 1855). Another treatise commonly used was from Winfield Scott, entitled Infantry Tactics, or Rules for Manoeuvers of the United States Infantry. Originally published in 1835, it was the standard drill manual for the U. S. Army. Other popular instruction manuals were issued early in the Civil War, including McClellan's Bayonet Drill (1862) and Casey's Infantry Tactics (1862).

Many generals, particularly early in the war, preferred to use Napoleonic tactics, despite the increased killing power of period weaponry. They marched their men out in tightly closed formations, often with soldiers elbow-to-elbow in double-rank battle lines, usually in brigade (by mid-war numbering about 2,500-3,000 infantrymen) or division (by mid-war numbering about 6,000-10,000 infantrymen) strength. This large mass presented an easy target for defenders, who could easily fire several volleys before his enemy would be close enough for hand-to-hand combat. The idea was to close on the enemy's position with this mass of soldiers and charge them with the bayonet, convincing the enemy to leave their position or be killed. At times, these soon-to-be outdated tactics contributed to high casualty lists.

Of particular tactical importance was the usage of skirmishers, usually small bodies of advanced troops which were often spaced several yards apart, and more specifically, five paces per man, according to Hardee's manual. They screened a defensive line from oncoming enemy soldiers, harassed attackers, probed enemy strength in preparation for an attack, and screened the assaulting columns. However, the skirmish formation was forfeited in most cases, for a line of battle was of preference. Skirmish formation would be used to take up large distances of an open front, which rarely occurred at the larger scale battles. Nevertheless, it was drilled into the recruits, should the opportunity to take skirmish formation arise in a combat scenario.

Assaults were carried out in several manners, including single or double rank battle lines with individual regiments side-by-side in a line of battle, assault waves (with multiple regiments or brigades in successive waves spaced out loosely one behind the other), brigade columns (all regiments of a brigade in line one behind the other in close formation), and other formations.

Weapons and equipment
Trained in the era of short-range smoothbore muskets, such as the Springfield Model 1842, which was issued to many units immediately prior to the war, many generals often did not fully appreciate or understand the importance and power of the new weapons introduced during the war, such as the 1861 Springfield musket and comparable rifles which had longer range and were more powerful than the weapons used by the antebellum armies. Its barrel contained several rifled grooves that provided increased accuracy, and fired a .58 caliber Minié ball (a small conical-shaped ball). This rifle had a deadly effect up to 600 yards and was capable of seriously wounding a man beyond 1,000 yards, unlike the previous muskets used during the American Revolutionary War and Napoleonic Wars, most of which had an effective range of only 100 yards.

Even smoothbore muskets underwent improvements: soldiers developed the technique of "buck and ball," loading the muskets with a combination of small pellets and a single round ball, effectively making their fire scattergun-like in effect. Other infantrymen went into combat armed with shotguns, pistols, knives, and assorted other killing instruments. Very early in the war, a few companies were armed with pikes. However, by the end of 1862, most infantrymen were armed with rifles, including imports from Great Britain, Belgium, and other European countries.

The typical Union soldier carried his musket, percussion cap box, cartridge box, a canteen, a knapsack, and other accouterments, in addition to any personal effects. By contrast, many Southern soldiers carried their possessions in a blanket roll worn around the shoulder and tied at the waist. They might have a wooden canteen, a linen or cotton haversack for food, and a knife or similar sidearm, as well as their musket.

One primary account of the typical infantryman came from James Gall, a representative of the United States Sanitary Commission, who observed Confederate infantrymen of Maj. Gen. Jubal A. Early in camp in the occupied borough of York, Pennsylvania, in late June 1863.