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The U.S. Defense Department

From , former About.com Guide

The headquarters of the U.S. Defense Department, the Pentagon

The headquarters of the U.S. Defense Department, the Penatagon

DoD Photo/Andy Dunaway

What Is It?:

The U.S. Department of Defense is responsible for leading and administering all American military forces and support operations. The department directs and coordinates the activities of the Army, Navy, Air Force and Marines in war fighting, peacekeeping, disaster relief, humanitarian aid, and homeland security.

History:

The individual branches of the U.S. military trace their roots back to America's declaration of independence. What was originally known as the War Department officially became the Defense Department in the 1940's. Today, the department is arguably the largest employer in the world with over three million people in the armed services, reserves, guard, and civilian support.

Leadership:

The department is led by the secretary of defense who is the agency's top ranking civilian. The top military leader is the Chairman of the Joint Chiefs of Staff. The "joint chiefs" are the heads of the Army, Navy, Air Force and Marines.

According to the Presidential Succession Law of 1947, the secretary of defense is sixth in line to succeed the president behind the vice president, speaker of the House, president pro tempore of the Senate, secretary of state, and secretary of the treasury.

Location:

The Defense Department is often referred to as "The Pentagon," a reference to its large, unique and five-sided headquarters building. With over 3.7 million square feet of floor space, the Pentagon is one of the largest buildings in the world.

U.S. Defense Department
The Pentagon
Washington, DC 20301

The department operates bases and ships around the globe with employees in over 163 countries..

Budget:

The President's 2007 budget for the Department of Defense totals $439.3 billion:

  • Military Personnel - $111 billion
  • Operation and Maintenance - $152 billion
  • Procurement - $84 billion
  • Research and Development - $74 billion
  • Other Programs - $18 billion

These budget figures do not include $50 billion the White House lists as "Estimated future emergency funding for the Global War on Terror."

Fun Fact:

The Pentagon has three times more floor space than the entire Empire State Building.

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