The Common Census Project draws various maps of the United States based on votes received from participants. The idea is to create a grass roots, non-scientific view about how the people themselves identify their communities apart from arbitrary political boundaries.
The main map is based on an answer the following question: “On the level of North America as a whole, what major city do you feel has the most cultural and economic influence on your area overall?” From this, they created a map of various “spheres of influence” of cities. Here’s the latest. You can get a bigger version by clicking:
I think this is an interesting map. It shows pretty much what I would intuitively expect in most regards. You expect Chicago to have a giant sphere of influence because it is so big. Dittos for the Twin Cities and Detroit because large areas of their state to the north lack comparable major cities. What jumps out at me though is St. Louis. It has a comparatively huge region, more than I would have expected. History and geography certainly play a role here. This also illustrates the comparatively small spheres of influence of places like Cincinnati and Louisville, which are hemmed in by other similar sized cities on all sides.
Getting to smaller places, I see all sorts of curious results. In Indiana, Evansville has a pretty sizable solar system around it. South Bend doesn’t even show up – it’s part of Chicago. Ft. Wayne is particularly interesting. It has a sort of crescent around it, but a good chunk of the area – including what appears to be the city of Ft. Wayne itself, is in the Indianapolis sphere. Or another interesting thing. Look at who says “Minneapolis” vs. “Twin Cities”.
Another way to slice this is by what is known as “economic areas“. The Bureau of Economic Analysis (part of the US Dept. of Commerce), uses these to measure trade areas. As they put it, “BEA’s economic areas define the relevant regional markets surrounding metropolitan or micropolitan statistical areas. They consist of one or more economic nodes – metropolitan or micropolitan statistical areas that serve as regional centers of economic activity – and the surrounding counties that are economically related to the nodes.” I’ve always considered this the best general purpose measure of the sphere of influence of a city. Here’s a map. Again, click for a larger version.
Of course, this measures the geographic size of the area. But what about the population? Here are the ranked populations for the 12 major metros that I focus on in this blog, ranked by order. These numbers are based on 2007 estimates.
- Chicago – 10,443,446 (ranked 3rd nationally)
- Detroit – 6,997,479 (9th)
- Minneapolis-St. Paul – 5,187,305 (13th)
- Cleveland – 4,604,932 (15th)
- St. Louis – 3,366,542 (19th)
- Indianapolis – 3,330,982 (20th)
- Pittsburgh – 2,879,762 (24th)
- Columbus – 2,607,561 (29th)
- Kansas City – 2,580,711 (30th)
- Cincinnati – 2,351,587 (32nd)
- Milwaukee – 2,323,196 (33rd)
- Louisville – 1,537,997 (52nd)
Again, these are interesting figures. You can see that some places, say Chicago and Louisville, have EA populations not much larger than their MSA population. Others, like Cleveland and Indianapolis, have significantly larger EA populations and rank much higher in the league tables here than you are used to seeing. I think this explains why those cities can sometimes punch above their weight. For example, whatever the MSA populations might indicate, Cleveland is still economically the biggest city in Ohio. This would be true even if Dayton were added to the Cincinnati EA. (Curiously that it is not part of a Cincinnati-Dayton area today, but rather the southern anchor of a Dayton-Springfield-Greenville EA. Something primed for a change on the next revision, perhaps?)
Lastly, I’ll leave you with a fun map. Common Census also does maps of fan area dominance for sports teams. In honor of the start of football season, I’ll include the NFL map, though they have one for every major sport. Again, click through for a larger version.