The Air Force began as a subdivision of the U.S. Army and was declared an official combatant arm in 1920. It wasn't until 1947, following World War II, that the Air Force was recognized as its own military branch.Today's Air Force operates in keeping with a three-part vision: global vigilance, reach and power. This vision empowers a technologically advanced force of more than 300,000 troops focused on air, space and cyberspace superiority.

The Air Force Reserve is an integral part of our country's dominant presence in air, space and cyberspace. With readiness as its primary charge, the Air Force Reserve contributes daily to the Air Force mission and is actively involved in Air Force operations around the world. The Air Force Reserve currently employs approximately 68,000 trained reservists. Though this makes up 20 percent of the Air Force's overall manpower, the extent of their contribution is much greater. More than 20 percent of all Air Force missions are accomplished through the efforts of Air Force reservists.

The Air National Guard was made an official component of the U.S. Air Force in 1947, following the great aerial battles of World War II. Like the Air Force Reserve, the Air National Guard is made up of Citizen Airmen who train part time, close to home, until called upon for duty. These professionals serve both the federal and state governments — assisting their communities and helping the U.S. Air Force guard America's skies. Today the Air National Guard is an essential component of the U.S. Air Force. Currently, this Force is made up of approximately 105,000 Air National Guard personnel. There are more than 140 Air National Guard units throughout the U.S. and its territories with varying service options for a Guardsman to choose from.

As the oldest branch of the U.S. military, founded in 1775, the Army is a powerful fighting force defending and serving our nation by land, sea and air. Elite groups within the Army, such as the Army Rangers and Special Forces, receive specialized training for advanced combat situations. In addition to domestic bases, the Army has permanent stations in Asia, Europe and the Middle East, as well as troops on the ground wherever there is a conflict. Length of individual service commitment varies, and in some cases may be as little as two years.

The Army Reserve offers people the opportunity to work in their civilian careers or attend college full time while serving near home. Army Reserve soldiers receive the same training as active-duty soldiers. After Basic Combat Training and Advanced Individual Training, Army Reserve soldiers return to their civilian lives and spend one weekend a month training to keep their skills sharp. For roughly two weeks a year, Army Reserve soldiers focus on challenging field and specialty training. They may even have the opportunity to attend competitive Army training programs such as Airborne and Air Assault schools. Service options for the Army Reserve range from three to six years.

Like the Army Reserve, the Army National Guard is made up of citizen-soldiers who train part time, close to home, until needed. Since 1636, each state has had its own militia. These became the foundation of today's Guard units (this was mandated by the Constitution in 1787). The Guard mobilizes to protect U.S. domestic interests in times of conflict or natural disaster and may be deployed internationally alongside full-time troops when the situation demands. Today's National Guard consists of approximately 340,000 troops from all U.S. states and territories.

The Coast Guard was created after five separate federal services were combined: the U.S. Lighthouse Service, the Revenue Cutter Service, the Steamboat Inspection Service, Bureau of Navigation and the U.S. Lifesaving Service. In 1915, a congressional act combined the Life-Saving Service and Revenue Cutter Service to form the Coast Guard. The Service was placed under the control of the Treasury Department until 1967, when an executive order transferred the Coast Guard to the newly formed Department of Transportation. Currently, the Coast Guard operates under the Department of Homeland Security during peacetime and under the Navy during wartime, or by special presidential order. In addition to protecting our nation's waterways, the approximately 40,000 active-duty members of the Coast Guard perform search and rescue, law enforcement and environmental cleanup operations.

The Coast Guard Reserve offers citizens the opportunity to serve on a part-time basis, while still serving their country and community. Reservists take part in maritime safety, mobility, security, national defense and the protection of natural resources. Today, approximately 6,000 Coast Guard reservists support and aid critical Coast Guard missions. Coast Guard reservists spend an average of one weekend a month and two weeks a year performing duties vital to our nation's security.

The United States Marine Corps was founded in 1775, even before our nation was officially formed. This elite group of men and women live by a strict code of integrity and ethics, producing not just strong warriors but people of exceptional character. The core values of honor, courage and commitment inform everything a Marine does, on and off the battlefield. The Marine Corps plays a major role as the first force on the ground in most conflicts. Today, approximately 180,000 Marines are stationed around the world at all times, ready to deploy quickly whenever and wherever needed. The commitment ranges from four to five years of service, but as the saying goes, "There are no ex-Marines or former Marines, simply Marines in different uniforms and in different phases of life."

The Marine Corps Reserve is critical to the Marine Corps' ability to provide a balanced, ready force. Many Marines come to the Reserve after serving on Active Duty, as the Reserve gives them an outlet to continue serving while pursuing a civilian career or furthering their education.

The U.S. Navy was founded under the authority of George Washington in 1775, with the intent to intercept British supply ships near Massachusetts. Despite success in battle during the American Revolution, a standing Navy was considered too large an expense for more than a decade. But, in 1794, pirate attacks on trade routes and increasing international conflicts cemented the importance of a strong Navy. Thus, began the force that, to this day, protects U.S. interests at home and abroad. Currently comprised of approximately 320,000 personnel, today's Navy is equipped to handle operations both on and under the sea, in the air and on the ground. Its reach is worldwide, spanning 100 international ports and touching the farthest corners of the open ocean. Elite groups within the Navy, such as the SEALs and Navy Divers, receive specialized training for advanced warfare situations. A Navy sailor generally serves a term of four years aboard one of the Navy's 271 deployable ships, though options for shorter time commitments exist.

The Navy Reserve is a valued partner of the Navy's active-duty department. It offers citizens the chance to serve on a part-time basis, training near home until called to active duty. A reservist can pursue a full-time civilian education or obtain special military training while serving. Today, the Navy Reserve is comprised of more than 20 percent of total Navy assets and, when called to action, can be found abroad, on shore, in the air or at sea. The Navy Reserve's involvement with the Navy continues to grow. Currently, approximately 47,000 Navy reservists stand by to join the fleet when needed as active parts of the largest and most powerful naval force in the world.