The World’s LARGEST Office Building

Let’s have a little general knowledge class today. So does anyone know what the world’s largest office building is? While we do have some large office space in Ottawa, the largest office space in the world is not located in Ottawa. Here’s a clue…it’s got 5 sides, it’s located in Virginia, near Washington, D.C., in the United States and it’s the headquarters of the U.S. Department of Defense. Yes, you guessed it – it’s the Pentagon!


The Pentagon is the largest office building in the world! It’s so big, that it’s the headquarters of all the military army services, which are the Army, the Air Force and the Navy. The building was constructed from 1941 – 1943 and it was made for the intention of uniting the War Department’s offices.  


Did you know that at first, the president at the time, Franklin D. Roosevelt, wanted the building to be constructed without windows, in an effort to deter any possible air raids?


Of course, later on he was convinced by engineers, that such a design would be unreasonable. The president then supported George Edwin Bergstrom’s five-sided design for the building. The site prior to the building was pretty much a swampy wasteland, which only had to small outdated Washington Airport.

  • The total cost of completing the building was $83 million dollars.
  • The building is made of steel and reinforced concrete, with limestone facing.
  • It covers an area of 29 acres, with a 5-acre central court.
  • There is 3,700,000 square feet of usable floor.
  • It can hold up to 25,000 people.
  • It has 5 floors, beside the basement and mezzanine.
  • There are 5 concentric pentagons, with spoke-like corridors connecting them.
  • “There are 17.5 miles (28 km) of corridors, but, because of its innovative construction, it is possible to walk between any two points within the building in approximately seven minutes.”
  • There are 7 libraries, 2 cafeterias, a dining room, seven snack bars, 67 acres of parking lots, bus and taxi terminals.


Some commercial offices in Ottawa aren’t even as big as the Pentagon’s dining room. Ha! Maybe you’re ready to get a new office building for your business in Ottawa and you're looking for the perfect office space to house your business and your products. You choose what’s right for you and we’re here to help find out what exactly is right for your business. We have different office structures in Ottawa and we’re sure we can find the best office space unit for you! If you are looking for office space in Ottawa for your dynamic and growing business then give us a call to speak with one of our office space representatives about our current inventory of great office spaces and retail spaces for your business in Ottawa.

The new development at 123 Slater is the perfect office space for your growing business and even for government office space in Ottawa with our different office layout types and all of the Ottawa office space amenities that we have available for your organization.