Insight Cartography

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Sources: Travis County | Williamson County | Hays County

I had so much fun going through all of the feedback, positive and negative, for my Urban Megaregions of the United States map. I’m really happy that so many of y’all enjoyed it. By far the most received request was for a more conservative version (or as I called it, the “boring version”), with higher population density requirements.

I’ll be the first to admit that the 20-persons-per-square-kilometer threshold that I set for the original map is extremely generous. To folks who live in high-density places like Europe, or in the Boston-Washington corridor, 20-persons-per-square-mile might as well be barren wasteland. Having grown up in West Texas, surrounded by actual barren wasteland, there is a world of difference to me, personally, between a population density of 0 and a population density of 20… but it’s all relative, I suppose.

The reason that I had set the cut-off so low was that I was trying to recreate the famous Emerging Megaregions map using objective criteria, and the only way to produce a map approaching something like Emerging Megaregions was to be extremely generous in defining what constituted an urban corridor. When you get right down to it, there is really only one true megalopolis in the United States, and that is the Boston-Washington corridor — and I didn’t see much use or fun in producing a map of U.S. megaregions with one lonely, solitary megalopolis. But, since y’all asked for it, here it is! The cutoff for this version is now 100-persons-per-square-kilometer.

To the good citizens of Philadelphia who recoiled in horror at my non-inclusion of Philadelphia in the list of major hubs for the Northeast Megalopolis, please accept my apologies. I did not intentionally omit Philadelphia — I was just using a little formula that I devised for calculating hubs, and Philadelphia just kinda got overshadowed by NYC. (My apology also extends to the good people of San Diego, San Jose, Fort Worth, and St. Paul, who suffered the same fate.) I discarded that methodology for this version, so please note that Philadelphia and San Jose are now designated as major hubs of their new, smaller regions. People of Philadelphia, please stop sending me vaguely threating Gritty memes. Thanks, jabronis.

Data source: U.S. Census Bureau.

Tools: Excel for data management, ArcGIS Pro for mapping, and GIMP for final design.

While I love the Emerging Megaregions map, one of the things that it has most inspired me to do is to take a stab at recreating the map on my own terms. Some elements of the map are a little… far-fetched. Literally. The “urban corridors” laid out in the report can be pretty heavy on the corridor and very light on the urban. This is the most common critique of the Emerging Megaregions map. For example, anyone who has ever taken a road trip in the Western United States can tell you just how ambitious some of the megaregions defined by America 2050 are. It is indeed quite difficult to imagine, for example, suburban sprawl someday spilling over the crest of the Rocky Mountains to join Salt Lake City with Denver, or the Gulf Coast industrial zone ever reaching all the way down the Texas coast to the Rio Grande.

I wasn’t there when Emerging Megaregions was being drawn up, but I think that it’s quite clear to anyone who has ever really analyzed the map that there was a rather large measure of artistic subjectivity (and maybe just a dash of an ideological penchant for ever-grander megaregions) applied to its creation. My ambition has thus been to create a better-in-some-ways megaregions map — one that is based on objective analysis as much as possible — and I think that I’ve finally done it! The only bit of subjectivity involved with my version is the naming of the megaregions. (I did my best… please go easy on me!) Other than that little bit of creative license, every other aspect of this map is purely a product of the precise methodology that I established when I began working on this project.

That doesn’t mean that there aren’t some results that some will find strange, annoying, or even downright offensive — just please know that I did not divide up the regions based on any preconceived notions, I did not choose their extents or the cities within them, and I did not at any point “cheat” and make an editorial decision when regions were either joined or separated by connections so small that you could probably jump over them, even when the results ran counter to my own notions of U.S. regions. If you’re unhappy with one or more of the results here, I apologize, but I am also preemptively passing the blame on to simple math and geography. (I will go into some of the oddities of this map below.)

So, thank you for enduring my disclaimer — now for the methodology! For this project, I used U.S. Census Tracts as my geographic units. If you’re not familiar with Census Tracts, think of a neighborhood in a large city, or perhaps a small suburb, or a cluster of neighboring farm towns. In the geographical hierarchy, they sit just below counties. If you’re familiar with the geography of U.S. counties, you know that they can be an awkward tool for delineating regions, with their arbitrary boundaries and wildly varying sizes. San Bernardino County in California, for example, is larger than nine entire U.S. states! Many of the enormous counties in the Western U.S., like San Bernardino, include both densely populated urban areas and vast uninhabited regions, meaning that if you try to use county boundaries to define metropolitan regions, you’re going to have to make some tough decisions — either incorporating large, empty areas into your metro, or leaving out the parts of said metro that happen to be just over the county line in a “rural” county.

Census Tracts avoid this problem by breaking counties down into their functional parts. There are about 74,000 tracts in the United States, so to get a sense of just how large a tract is, that averages out to about 4,500 residents per tract (330 million ÷ 74,000). Census Tracts are also great because the Census Bureau regularly updates their data at the tract-level, so recent and complete data is always available. For this map, I was able to use population data for 2019. Finally, the tracts are contiguous, meaning that you don’t have to mess with city boundaries that can be all over the place, or figure out how to deal with the many unincorporated suburban and exurban communities that make of so much of our inter-city corridors.

So, I collected all of the data, located all tracts with a population density of 20 persons per square kilometer (that’s 50 persons per square mile for you imperial hold-outs), and then clustered all of those tracts. If any part of two tracts touched, they were merged, regardless of any other circumstances. This method resulted in some enormous networks of clusters in the densely populated Eastern U.S. — namely three super-megaregions: the Northeast, the Great Lakes, and the Upper South. In addition to the three big boys, there were 18 other smaller clusters that each reached a population of 2 million. And that’s basically it! The result is a map of 21 urban megaregions, defined objectively by measurable criteria and free from the whims of the mortal geographer.

Okay, so here some of the weird, counterintuitive, and frustrating things that came up with this methodology:

• Almost-regions: The Puget Sound (Seattle) and the Willamette Valley (Portland) come within about 15 km of touching, almost-but-not-quite meeting at the Columbia River and forming a combined Cascadia megaregion. San Francisco Bay and Sacramento-San Joaquin come within about 10 km of touching in a couple of spots, almost forming a combined Northern California megaregion. The “Texas Triangle” megaregion is probably still at least a generation away from becoming a reality, but right now only about 50 km separate the San Antonio-Austin corridor from both Dallas-Fort Worth and Greater Houston. Much to my horror, New Orleans, the crown jewel of the Gulf Coast, is separated by a hair’s width from Baton Rouge and thus from the rest of the Gulf Coast megaregion. That one hurt. For the grand finale, the three super-megaregions of the Eastern U.S. — The Northeast, the Great Lakes, and the Upper South, all come within distances of about 10 km or less of all merging into an Eastern U.S. ultra-region (along with Western New York) that would be home to half of the U.S. population. In most of these cases, the distances and differences in density are so small that I would expect for most of these almost-regions to fully merge when I update this map with 2020 or 2021 data.
• Barely-regions: Some of the megaregions are nice and solid, like the Northeast Megalopolis, but some are only held together by a thread. The Chicago-Detroit region ever so slightly touches the Cleveland-Cincinnati region near Toledo to form the Great Lakes megaregion. Further south, Birmingham is barely hanging onto Atlanta and the Upper South megaregion, while Nashville is only there because it, in turn, is barely hanging onto Birmingham. And there are countless smaller cities and corridors that come very close to merging into their neighboring megaregions or forming new ones, such as in the Central Valley of California, which could eventually form the spine of a California super-megaregion.
• Regional names: Some were obvious, like San Francisco Bay. Some were not so obvious, and I did my best to give the regions names that would balance familiarity with geographical accuracy. A couple of the megaregions, like San Antonio-Austin and Sacramento-San Joaquin don’t even really have good names yet. Some lone-wolf cities, like St. Louis, don’t even seem to have names for their regions other than just the name of the principal city. And then there were some regional names that came close to properly identifying and describing one of the megaregions, but with some crucial flaw. (I’m sure that I’ll be called out for using “Upper South” to describe a region that definitely dips down into the Deep South in parts, but there is just no other name for it, and it was certainly a better choice than “Upland South”. I realize that Emerging Megaregions had a name for this region — “Piedmont Atlantic” — but that is a name that, as far as I can tell, is only used by people referencing Emerging Megaregions, and I wanted to avoid using “made-up” names as much as possible.)
• Finally, if you have a bone to pick about a city that was included or left out of the “Major Hubs” column, I had a methodology for that too. It is too boring to go into here, but basically the component cities were weighted based on their size relative to the principal city. So, smaller megaregion = smaller hubs; larger megaregion = only the very largest hubs. I have nothing against your hometown, I swear! Nor do I have anything against Hawaii or Alaska — they were included in the data set but just didn’t produce any megaregions.

This map definitely has its limitations. At the end of the day, even Census Tracts occasionally have arbitrary boundaries which will affect the outcome of the methodology. Going down to the next level, Census Block Groups, would be ideal, but would involve exponentially more computing power. The other major limitation also comes down to data availability: I would love to be able to include Mexican and Canadian border districts. I guess what I’m saying is that this is “version 1”, with updates to hopefully follow.

TLDR: Took all of the neighborhoods and towns in the U.S. that are moderately populated, clustered them together, identified the largest clusters, and put them on a map with funny names.

Data source: U.S. Census Bureau.

Tools: Excel for data management, ArcGIS Pro for mapping, and GIMP for final design.

Click here for interactive version, or here for project data.

Methodology:  All local Subreddits with Reddit gold awards representing 100+ hours of server time were cataloged and combined by U.S. Census metropolitan area (Primary Statistical Area). Cumulative Reddit Gold and Gold per capita were calculated in aggregate for each metropolitan area.

This map shows where Texans living in 1850 had been born.  Native-born Texans made up only a quarter of the population in 1850.

Methodology: Race and ethnicity data taken from US Census Bureau; religious affiliation data taken from Pew Research Center; voting data taken from US Federal Elections Commission. Within each category, each state’s demographic composition was compared to that of the entire country. States with less variation from the national composition scored higher (more average). The composite score is the average of the three category scores. Category groupings for race and ethnicity include: Hispanic (any race), Non-Hispanic White, Non-Hispanic Black, and Non-Hispanic Other. Category groupings for religious affiliation include: Evangelical Protestant, Mainline Protestant, Black Protestant, Catholic, Other Christian, Other Religion, and Unaffiliated. Categories for political affiliation include: Democratic, Republican, and Other. (Party affiliation determined by averaged results of presidential elections 2004-2016.)

The 50 states (+DC) redrawn such that no metropolitan area crosses state lines

Methodology: I used Designated Market Areas (DMAs) as opposed to Census-defined metropolitan areas, as the Census-defined areas are non-contiguous and somewhat arbitrary (and also made for a far less interesting map when I tried using them initially). For those unfamiliar with DMAs, you can think of them as clusters of counties that all share the same local news stations. As such, they are a good bit broader than Census Metropolitan Statistical Areas (MSAs) and generally each incorporate several MSAs as well as non-urban areas. Each “new” state is made up of all counties that make up its DMAs, with the multi-state DMAs being given to the principal city within the DMA.

There are three notable exceptions, as this methodology, strictly followed, eliminates the states of New Hampshire (would be split up between Maine, Massachusetts, and Vermont), New Jersey (would be split up between New York and Pennsylvania), and Delaware (would be split up between Maryland and Pennsylvania). Therefore, in order to “preserve” the 50 states as they currently exist, Portland, Maine, has been relocated to New Hampshire, Philadelphia has been relocated to New Jersey, and Salisbury, Maryland, has been relocated to Delaware. I treated Washington, DC, as a state, so it now incorporates the entire Washington metropolitan area. Wyoming was also a bit tricky, with its two regions (Cheyenne and Casper) being non-contiguous and Cheyenne itself being an enclave within the Denver region. So, some editorial decisions were made there. The last caveat is that the Paducah, Kentucky, region was separated from the rest of Kentucky by the intervening Evansville, Indiana, region, and was thus given to Missouri, which is home to Cape Girardeau, the second principal city in the region.