The Pentagon has twice as many bathrooms as necessary. When it was built in the 1940s, the State of Virginia still had segregation laws requiring separate toilet facilities for blacks and whites.

The Pentagon building spans 28.7 acres (116,000 m2), and includes an additional 5.1 acres (21,000 m2) as a central courtyard. It has five façades, listed starting with the north side and moving clockwise: the Mall Terrace Entrance façade, the River Terrace Entrance façade, the Concourse Entrance (or Metro Station) façade, the South Parking Entrance façade, and the Heliport façade. On the north side of the building, the Mall Entrance, which also features a portico, leads out to a 600 ft (180 m) long terrace that is used for ceremonies. The River Entrance, which features a portico projecting out 20 ft (6.1 m), is located on the northeast side, overlooking the lagoon and facing Washington. A stepped terrace on the River Entrance leads down to the lagoon; and a landing dock was used until the late 1960s to ferry personnel between Bolling Air Force Base and the Pentagon. The main entrance for visitors is located on the southeast side, where the Pentagon Metro station and the bus station are located. There is also a concourse on the southeast side of the second floor of the building, which contains a mini-shopping mall. The Pentagon’s south parking lot is located on the southwest side of the Pentagon, and the west side of the Pentagon faces Washington Boulevard.

The concentric rings are designated from the center out as “A” through “E” (with in addition “F” and “G” in the basement). “E” Ring offices are the only ones with outside views and are generally occupied by senior officials. Office numbers go clockwise around each of the rings, and have two parts: a nearest-corridor number (1 to 10) followed by a bay number (00 to 99), so office numbers range from 100 to 1099. These corridors radiate out from the central courtyard, with corridor 1 beginning with the Concourse’s south end. Each numbered radial corridor intersects with the corresponding numbered group of offices (for example, corridor 5 divides the 500 series office block). There are a number of historical displays in the building, particularly in the “A” and “E” rings.

Floors in The Pentagon are lettered “B” for Basement and “M” for Mezzanine, both of which are below ground level. The concourse is located on the second floor at the metro entrance. Above ground floors are numbered 1 to 5. Room numbers are given as the floor, concentric ring, and office number (which is in turn the nearest corridor number followed by the bay number). Thus, office 2B315 is on the second floor, B ring, and nearest to corridor 3 (between corridors 2 and 3). One way to get to this office would be to go to the second floor, get to the A (innermost) ring, go to and take corridor 3, and then turn left on ring B to get to bay 15.

It is possible for a person to walk between any two points in the Pentagon in less than seven minutes.

Just south of the Pentagon are Pentagon City and Crystal City, extensive shopping and high-density residential districts in Arlington. Arlington National Cemeteryis to the north. The Washington Metro Pentagon station is also located at the Pentagon, on the Blue and Yellow Lines. The Pentagon is surrounded by the relatively complex Pentagon road network.

The United States Postal Service has established six ZIP Codes for The Pentagon, to which the place name “Washington, D.C.” is assigned, even though The Pentagon is actually located in Virginia. The Secretary of Defense, the Joint Chiefs of Staff, and the four service branches each have their own designated ZIP Code.