Army

• The United States Army was established in 1784. With more than 500,000 active duty soldiers, the Army is the largest fighting force in the country. The Army is responsible for most of the military's land operations. Aside from active duty soldiers, the Army includes members of the Army Reserves. The reserves are part-time soldiers that train once a week throughout the year. Reserve soldiers may be called to active duty in times of war if they are needed. After their tour of duty, they are returned to part-time reserve status.
  
  

Army National Guard

• The National Guard is a subdivision of the United States Army. National Guard soldiers are part-time unless called to active duty. The National Guard is responsible for assisting cities and citizens after emergencies or national disasters such as floods, hurricanes and tornadoes. They can be called to serve anywhere in the country, and during wartime may be sent to other places throughout the world.
  
  

Navy

• Formed in 1794, the Navy is responsible for water-based operations. Navy soldiers serve on aircraft carriers, destroyers and other military ships. The Navy is in charge of sea-based military operations during peace and wartime. The Navy is one of the most mobile branches of the U.S. Armed Forces.
  
  

Air Force

• In 1947, the Army Air Corps separated from the United States Army to form its own branch of the U.S. military. This branch is known as the Air Force. More than 250,000 active duty personnel make up the United States Air Force. This branch of the military is in charge of airborne operations. With thousands of aircraft at its disposal, the U.S. Air Force is the largest airborne force in the world. It relies on both manned and un-manned aircraft to carry out its missions.
  
  

Marine Corps

• The United States Marine Corps works closely with the Navy to carry out amphibious operations. The Marines have existed since the Revolutionary War, though they used to be considered a sub-branch of the Navy. The Marine Corps takes charge of unusual or special military situations and has participated in every conflict that the U.S. has been involved in since the Revolutionary War. Marines are responsible for security at the White House and the Department of Defense. They also serve as security at Camp David and aboard Air Force One.
  
  

Coast Guard

• The oldest sea-based branch of the military in the United States is the Coast Guard. This branch of the Armed Forces is responsible for securing the country's coasts and waterways. Members of the Coast Guard are required to complete an eight-week boot camp, as with other branches of the military. The Coast Guard possesses law-enforcement authority that the Navy lacks, and often works with the Navy to accomplish goals and missions. Unlike other military branches, all Coast Guard positions, including combat positions, are available to women as well as men.