Army unit patches denote the headquarters to which a soldier is assigned, and the patches are required on every U.S. Army uniform. These patches are generally placed on the upper arm of uniforms and are also known as shoulder sleeve insignias. The division insignias for the 1st Armored, Cavalry and Infantry divisions of the U.S. Army are recognizable examples of Army unit patches.
The 1st Cavalry Division, based in Fort Hood, Texas, uses the traditional yellow cavalry color on the background of its division insignia. The black horse head in the upper right corner of the shield pays homage to the equestrian roots of cavalry formations, while the use of black denoting iron commemorates the transition to armored vehicles. The black bar that separates the diagonals of the shield represents a sword baldric.
Formed in 1917, the 1st Infantry is the oldest continuously serving unit in the Army. The 1st Infantry Division's nickname, "The Big Red One," derives from its shoulder sleeve insignia, a red numeral "1" on an olive green background.
As of 2014, the 1st Armored Division is the sole active armored division in the United States Army. Its unit patch is triangular, and the background colors are blue, yellow and red. The center of the patch shows tank tracks under the emblem of a gun. A red lightning bolt transects the other symbols, and the unit's nickname,"Old Ironsides," is printed at the bottom.