The Pentagon is dedicated in Arlington County, Virginia.

The Pentagon is the headquarters building of the United States Department of Defense, in Arlington County, Virginia, across the Potomac River from Washington, D.C. The building was constructed on an accelerated schedule during World War II. As a symbol of the U.S. military, the phrase The Pentagon is often used as a metonym for the Department of Defense and its leadership.

Arlington County, or simply Arlington, is a county in the U.S. state of Virginia. The county, which is located in the Washington metropolitan area and the broader Northern Virginia region, is positioned directly across from Washington, D.C., the national capital, on the southwestern bank of the Potomac River. The smallest self-governing county in the United States by area, Arlington has both suburban and urbanized districts, the latter being concentrated around corridors along several Washington Metro lines. Its seat of government is located in the Court House neighborhood, which hosts many of its administrative offices and county courthouse.