After explaining the concept of an edge city to my American Suburbanization class, a discussion arose about how much space these places really have. When defining the edge city, Joel Garreau had these as two criteria (out of five total): “has five million square feet or more of leasable office space” and “has 600,000 square feet or more of leasable retail space.” This is a lot of space, as much as a smaller big city, but can still be hard to understand.

For example, there is much more commercial and retail space in the exemplar of the edge city: Tysons Corner, Virginia.

Around 2007 Tysons Corner had 25,599,065 square feet (2,378,231.0 m2) of office space, 1,072,874 square feet (99,673.3 m2) of industrial/flex space, 4,054,096 square feet (376,637.8 m2) of retail space, and 2,551,579 square feet (237,049.4 m2) of hotel space. Therefore Tysons Corner has a grand total of 33,278,014 square feet (3,091,628.7 m2) of commercial space.

How do we put this in more manageable terms?

1. Garreau compares this suburban space to the office and retail space in existing cities. The 5 million square feet of office space “is more than downtown Memphis.” While we may have traditionally associated this much office and retail space only with the downtowns of big cities, now concentrations of this space can be found right in the middle of the suburbs. This is unusual because suburbs are often portrayed as bedroom suburbs, places like people live and sleep but have to work elsewhere.

2. Compare this space to large buildings. The Willis (Sears) Tower in Chicago has 4.56 million square feet of space, 3.81 million rentable. So an edge city would have at least slightly more space this notable office building though perhaps it is difficult to visualize this space since it is a skyscraper and each floor seems smaller. An ever bigger building, The Pentagon, has 6.5 million square feet, more than the lower threshold for an edge city. Therefore, Tysons Corner has nearly 4 Pentagons of office space. Comparing this edge city space to shopping malls, Woodfield Mall in Schaumburg, Illinois (an edge city itself) has 2.7 million square feet while the Mall of America has a total of 4.2 million square feet.

3. We could measure edge cities in terms of square miles or acres and then compare to bigger cities. Square miles make some sense: Tysons Corner is 4.9 square miles while Memphis, a city Garreau says has downtown space similar to that of an edge city, is 302.3 square miles (on land). Acres are a little harder to interpret: a common suburban house lot is an eighth of an acre, a square mile has 640 acres (hence the dividing of the American frontier into 160 and 640 acre plots), and an acre has roughly 43,500 square feet. Then, an edge city with 5 million square feet of office space has about 115 acres of office space. Perhaps acres are best left to farmers.

In the end, I think Garreau made the right comparison to demonstrate the office and retail space within an edge city: we have some ideas about the size of downtowns of smaller big cities and the image of this amount of space existing in the suburbs is jarring.