If “Inside the Beltway” were a city, how would it compare to other major cities? It would be almost the size of Los Angeles but half as dense

a little larger in area than Chicago but less dense than Los Angeles.

Image by Michael Rodriguez. Click for interactive version.

The latest Census data show that Montgomery County reached 1 million people, a statistic that has gotten a lot of worthy attention. Still, let’s remember that jurisdiction boundaries are pretty arbitrary. As commenter AlanF also pointed out, DC, Arlington, and Alexandria (the “core jurisdictions”) have just about reached 1 million as well (999,662 as of the latest Census estimates).

Michael Rodriguez decided to analyze “inside the Beltway” as if it were its own city. Given the way the Beltway separates communities, it’s a good natural boundary and means more than the artificial lines between counties or between DC and Maryland.

Inside-the-Beltway would have about 1.7 million people. in 423 square miles. That’s a little smaller than Los Angeles and only about half the density of people per square mile.

Update: Commenter npm points out that Rodriguez’s table appears to be incorrect, and “Inside the Beltway’s” density may be more like 80% of Los Angeles’ rather than 50%.

Table by Michael Rodriguez.

Update 2: A reader with access to GIS systems has estimated the land and water area of “Inside the Beltway.” Plugging in those numbers, and assuming that the other numbers on the table are correct, the table would look like this.

Update 3: Rodriguez has updated his post and fixed the errors in the DC and “Inside the Beltway” numbers. I’ve updated the table to reflect them.

Geography Total area (sq. mi.) Water area (sq. mi.) Land area (sq. mi.) Population Density (Pop./sq. mi.) Inside DC Beltway 266 10 256 1,725,686 6,749 District of Columbia 68 7 61 632,323 10,298 New York City 469 166 302 8,336,697 27,541 Los Angeles 503 34 469 3,792,621 8,087 Chicago 234 7 227 2,707,120 11,920 San Francisco 232 185 47 805,235 17,177

The lower density than Los Angeles comes because most of the land inside the Beltway is actually not very dense, except for central DC, Capitol Hill, along Georgia Avenue, the Rosslyn-Ballston corridor, bits of Silver Spring and College Park, and a few other places.

Density by census tract. Image by Michael Rodriguez. Click for interactive version.

Also, if “inside the Beltway” were a city, metonymy in the national press would be even more severe than it is today.