The following is a quick look at the organization of the U.S. Army:
• The largest army component is the U.S. Army Forces Command (FORSCOM), which executes the land defense of the U.S., provides military support to civil authorities and trains, sustains, mobilizes and protects strategic land forces worldwide.
• The army has over 400,000 enlisted soldiers and 76,000 officers.
• With headquarters in Atlanta, Ga., the U.S. Army Reserve consists of about 250,000 soldiers. It fields a large portion of the support staff, especially in civil affairs, engineering, transportation and maintenance.
• The Army National Guard fields approximately 370,000 troops (not including Alaska, Hawaii and Guam). It can provide FORSCOM with eight combat divisions, one armored cavalry regiment and 21 combat brigades.
• Secretary of the Army: The secretary is the civilian head of the United States Army and reports to the secretary of defense for operational authority. Responsible for organizing; training and equipping strategic land combat forces, he is named by the president and approved by the Senate.
• Chief of Staff of the Army: The link between the civilian secretary and army components, he serves as an adviser to the secretary and implements his directions. The chief of staff is appointed by the president for a term of four years.
• Infantry: These ground troops engage the enemy with small arms and other light weapon systems.
• Armor/Cavalry: This branch includes soldiers in tanks or in reconnaissance wheeled vehicles.
• Field Artillery: These soldiers take out the enemy from miles away with cannon, rocket and missile fire.
• Aviation: Using helicopters and fixed-wing aircraft, these troops fly combat missions and provide combat service support.
• Military Intelligence: These soldiers gather important data about the enemy for use in the field.
• Squad: The smallest groupings in the army structure, squads are made up of 8 to 11 soldiers and are normally led by a sergeant.
• Platoon: Usually consisting of two to four squads, platoons are typically led by a lieutenant, with a senior sergeant second in command.
• Company (in the infantry), battery (in the artillery) or troop (in the cavalry): The company, battery or troop is made up of three to five platoons and is typically commanded by a captain. It usually has a first lieutenant as the second in command and a first sergeant as the senior non-commissioned officer.
• Battalion: The primary combat maneuver element of the Army, the battalion or squadron is composed of four to six companies and is commanded by a lieutenant colonel with a sergeant major as the senior non-commissioned adviser. A major acts as the executive officer and second in command. The battalion is tactically and administratively self-sufficient and can conduct independent operations of a limited scope. An armored or air cavalry unit of similar size to a battalion is called a squadron.
• Brigade: The brigade or regiment is made up of two to five battalions under the command of a colonel with a sergeant major as the senior non-commissioned officer. Armored calvary and ranger units of similar size to a brigade are called regiments, while special forces units are known as groups.
• Division: Typically made up of three maneuver brigades, as well combat support brigades, they are commanded by a major general. The division performs major tactical operations for the corps and is capable of sustained operations.
• Corps: A corps is made of two or more divisions commanded by a lieutenant general. At this level, national intelligence assets are analyzed and command and control of the whole theater operations are coordinated.
• Army: Armies can be identified as theater armies, field armies, or army groups.
• Lieutenant General
• Major General
• Brigadier General
• Lieutenant Colonel
• 1st. Lieutenant
• 2nd. Lieutenant
• Sergeant Major
• First Sergeant
• Sergeant First Class
• Staff Sergeant
• Specialist 4th Class
• Private First Class
Warrant officers are highly specialized, single-track specialty officers appointed by the Secretary of the Army, based upon a sound level of technical and tactical competence.
The Army Warrant Officer Corps consists of 25,000 men and women of both the active Army and the reserves. There are five grades within Corps, stretching from Warrant Officer through Chief Warrant Officer Five.
Source: U.S. Army, U.S. Military Academy and Global Security.org