Flags serve many purposes. They symbolize a people and represent national pride. Flags convey a shared history. Over the centuries, military units have carried flags and colors. Colors and flags affirm group identity. They build pride and morale, and represent the group's honor. In battle, flags served as a rallying point when a formation was broken. Troops gathered around the flag to regroup, attack or retreat. Flags marked specific individuals, locations and functions such as hospitals and ambulances.

Infantry regiments regularly held trooping ceremonies. Colors were paraded up and down the line of assembled soldiers to music to make sure the men remembered the colors. A guard of non-commissioned officers usually protected flags and colors. Held in great reverence, a regiment's honor was embodied in its colors. The entire regiment was humiliated if its colors were lost in battle.

From the establishment of the United States Army in 1785, US regular infantry regiments carried colors. Regiments didn't carry the United States flag, as it was felt that no one unit could carry the national honor into battle. By the 1840's, the infantry carried the United States flag with the regimental number or title printed on one of the white stripes. If the flag was lost in battle, only that regiment's honor, and not the national honor, was lost. During the Civil War, a soldier who captured enemy colors or saved his unit's colors frequently was honored. In addition to receiving a medal honor, a soldier was sometimes given a leave of absence. Soldiers who captured enemy colors were often mentioned in dispatches or listed on a role of honor.

At the start of the Civil War in 1861, Northern and Southern units came to the front with their own flags and colors. Women of the unit's hometown made and presented flags to their men. Many companies had their own distinctive flag designs. Since most regiments contained 10 companies, the number of flags could be overwhelming. Officers soon realized that the huge number was dangerous because soldiers' lives depended on quick identification of flags.

The number of flags was reduced. A federal regiment carried 2 flags, one was the American flag and the other was a regimental flag. A Confederate regiment usually carried a battle flag. A Union infantry regiment carried the national color and a state or regimental color. The national color included the regimental name. The state or regimental color, usually dark blue, had the state crest painted at its center. Other branches of the Service carried colors, generally of a smaller size. Union Army Major General Joseph Hooker introduced a system of flags and badges to identify different commands.

Forts were supplied with flags of 2 sizes. The larger flag was the garrison flag, and the smaller, the storm flag that was flown in bad weather. The Confederacy adopted its own national flag, called the First National Flag, on March 4, 1861. During the course of the war, the Confederacy had 3 different National Flag designs.

When the southern armies surrendered in 1865, their battle flags generally were sent to the War Department. Later, in an effort promote reconciliation, President Theodore Roosevelt issued an order to return the flags to the southern states. In the North, soldiers returning from the war, placed their flags in various state capitals where most can be seen today.