Subterranean floors in the Pentagon are lettered "B" for Basement and "M" for Mezzanine. The concourse is 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.[12]
It is possible for a person to walk between any two points in the Pentagon in less than ten minutes, though the most optimal route may involve a brisk walk, routing through the open-air central courtyard, or both.[13][14][15] The complex includes eating and exercise facilities, and meditation and prayer rooms.
Just south of the Pentagon are Pentagon City and Crystal City, extensive shopping, business, and high-density residential districts in Arlington. Arlington National Cemetery is to the north. The Pentagon is surrounded by the relatively complex Pentagon road network.[16]
The Pentagon has six Washington, DC, ZIP Codes (despite its location in Virginia): The Secretary of Defense, the Joint Chiefs of Staff, and the four service branches each have their own ZIP Code.[17]