In a previous post, I wrote about some of the ways that people have proposed partitioning the United States (in relatively large chunks; a future post will discuss why I'm not interested in proposals to carve off little pieces). This time, I'm going to lay some groundwork for a geography-based partition that is seldom considered. The mesh-based population cartogram shown in this post suggests the starting point.
The Great Plains region occupies portions of ten states. In the upper map to the left, the Great Plains counties in those states are shown in white, and the remaining portions of the states in various colors. I've intentionally left out any state boundaries within the white area in order to emphasize the point that I'm writing about a situation that is regional rather than state-based.
There have been a lot of different definitions of the Great Plains over the years , so it's worth saying where this one came from. I started with the US Census Bureau's publication Population Dynamics of the
Great Plains: 1950 to 2007 . Then I removed seven counties from the Front Range area of Colorado and four counties from the Austin area in Texas. I had three reasons for trimming out those 11 counties: (1) they sit on the periphery of the Plains and different standards might or might not include them; (2) they have grown enormously in population for reasons that have nothing to do with the Plains; and (3) that large population growth doesn't fit my narrative. Sometimes there are just outliers in the data that should be excluded.
The Great Plains as shown here is a large region: somewhat smaller than Alaska but almost twice the size of Texas; 50% larger than the Pacific Coast states of California, Oregon, and Washington combined; 20% larger than the 15 Atlantic Coast states combined. The Great Plains are also quite empty, at least so far as people go. The lower cartogram resizes each county based on its population. The Plains don't exactly disappear, but they become a narrow strip. The strip is less narrow at the north and south ends, where there are large fossil-fuel deposits that have been or are being developed. Many parts of the Plains are getting emptier as time goes on, with populations that are shrinking in absolute terms.
This is a long-term trend; the Census Bureau document mentioned above identifies a large number of counties whose population peaked more than 80 years ago. Nor is the population situation likely to reverse itself. Agriculture has become increasingly mechanized, requiring fewer people. The same is true for the energy resources that occur in some parts of the Plains: it doesn't take a lot of people to extract a million tons of coal from a Wyoming surface mine, or to maintain a large wind farm, or to drill the oil wells in the Bakken area of North Dakota. Generally speaking, the area lacks the kinds of infrastructure that would attract businesses that aren't concerned with natural resources. In many cases, the infrastructure -- in the sense of services like medical care or education -- are declining.
In a future where distance becomes more important than it is today, the wide, empty expanse of the Great Plains is a natural dividing line between eastern and western parts of the country. Always keep in mind the scale of things: the width of the Plains ranges from 250 to about 550 miles. Compared to the Boston-to-Washington, DC megalopolis, the Plains have eight times the area but only one-tenth the population. Even in a local comparison, the bulk of the Front Range population -- the large yellow bulge on the cartogram -- lives in a strip 30 miles or so wide on that portion of the Plains immediately adjacent to the Rocky Mountain foothills.
The next question to consider is "Are there important differences in the two parts of the country separated by the Great Plains?" In the next post in this series, I'll show a variety of such differences.
 There has always been some uncertainty about the dividing line between wetter, lower-altitude prairie and the drier, higher Great Plains. Some cartographers extend the Plains much farther to the east, including parts of Minnesota and Iowa. Some definitions also stop the Plains on the south end before they reach the Rio Grande, asserting that that area becomes so dry that it should be categorized as desert.
 Unlike some works, in this one the authors did not include a list of which counties they had chosen. That's a shame, given that there are FIPS (federal information processing standards) codes for every county and county-equivalent in the country, and lots of useful data indexed by FIPS code. I generated my list after a relatively miserable afternoon spent with Figure 6 from the publication and some other information sources.