Army divisions are units consisting of anywhere from 10,000 to 30,000 soldiers and their support staff. Each carries an identifier describing the type of unit. The types of divisions are infantry, airborne, mountain, cavalry and armored.
Infantry divisions largely consist of foot soldiers, while airborne divisions contain troops specialized in parachute assault. Mountain divisions contain soldiers trained in high-altitude operations. Cavalry units emphasize speed and can use ground vehicles or helicopters. Armored divisions contain tanks and other heavy artillery.
Originally, divisions were temporary designations of troops. General Washington established three divisions for the Revolutionary War, and during the Civil War, large army corps were traditionally divided into three divisions. The first permanent divisions were established during World War I, creating units that would develop their own histories and esprit de corps over time. The division remained the base element of the United States Army until the 21st century, when the focus shifted to brigade-sized and smaller units.
As of 2014, there have been a total of 128 permanent Army divisions, although most of them were only active during particular conflicts. Famous divisions include the First Cavalry Division, First Armored Division and 10th Mountain Division. Many divisions have unique nicknames, such as the First Infantry Division, known as "Big Red One," and the 101st Airborne, known as the "Screaming Eagles."