I previously voiced skepticism about the concept of mega-regions. I used as an example the cities of Indianapolis, Louisville, and Cincinnati, which are close enough geographically that they seem like a logical expanded region, yet found few practical ways for those cities to collaborate.
Well, Jeff of Daytonology turned me onto this handy web site at the Fort Worth Star-Telegram that provides easy clickable access to migration data. It shows the estimated migration from county to county in the United States from 2000-2005 based on IRS tax return data. This is a standard source for intra-census migration figures. The Census Bureau has downloadable raw data files, but I’ve not found the leisure time to create a database of it.
In the meantime, I used the web data above to draw the following chart. It shows the migration between our proposed super-region of Indianapolis, Louisville, and Cincinnati. For fun, I threw in Columbus.
I notice a few things. Firstly, the Cincy-Columbus flow is by far the heaviest, showing the importance of in-state ties. I wonder how much of this could be accounted for by Ohio State University? Also, the Louisville-Columbus flow is the weakest, as one would expect from the greater distance between those cities. Indianapolis is the domestic migration champion of the Midwest, and these figures show this, as Indy has a modestly positive migration balance with all three cities.
I’m not sure what conclusions can be drawn from this. But it represents a data point to consider.