The United States is the third most populous country in the world, made up of nearly 20,000 cities and towns and 333 million people.
Dividing these population groups into a cohesive framework of statistical areas is no easy task, and the latest US Census Bureau map shows just how complex the task is.
This huge map, which covers the entire country including Puerto Rico, includes 392 metropolitan statistical areas and 547 micropolitan statistical areas.
From the metro to the microphone
The wide variety of population models across the country can make it difficult to divide regions into uniform units. There are two main divisions to consider when viewing this map:
- Metropolitan regions (metropolitan areas) have at least an urban core of at least 50,000 inhabitants. They are the largest centers of population, sometimes encompassing many counties. In some cases, these metropolitan areas are further subdivided into Metropolitan divisions.
- Micropolitan areas are the smallest areas measured on this map (indicated by a lighter shade of green). These smaller regions, which are generally located further from large cities, have at least an urban core of at least 10,000 but less than 50,000 inhabitants.
One thing to note about all of these definitions is that cities in these regions must have significant links with a neighboring region, usually in the form of commuting links. This is what justifies linking adjacent counties in a measurable area.
Another unique layer of data on this map is the shading which indicates the actual urbanized area in metropolitan areas. In the Atlanta-Sandy Springs-Alpharetta example, it’s easy to see how urban sprawl has extended the urban area to a number of neighboring counties.
In this context, we’ll take a closer look at three points of interest on the map that show this concept at work with varying degrees of complexity.
Level 1: The central city
The Texas Triangle offers what is perhaps the simplest example of metropolitan areas.
As seen above, Houston, Austin, and San Antonio anchor their respective regions, and the surrounding counties are grouped into a metropolitan area. The surrounding counties have all been identified as having links to the central county, and in some cases the urban area has expanded to the neighboring county over time.
Level two: the city cluster
The region anchored by Salt Lake City requires more thought to divide into statistical zones.
While there are a number of population centers in the region, including Salt Lake City, Provo, and Ogden, they all have enough economic “magnetic pull” to warrant dividing the region into separate statistical areas.
Of course, regions are constantly changing, and sometimes those areas are updated. Salt Lake City and Ogden were previously combined into a single metropolitan area, but were separated in 2005.
Level three: the mega-region
New York City is the ultimate challenge for planners looking to categorize population centers into a clean and tidy statistical box.
On the one hand, the contiguous urban area is massive, stretching from the west side of Long Island to the east side of New Jersey. In addition to New York City itself, the metropolitan area includes 19 other municipalities with populations over 100,000.
Second, NYC is an unprecedented economic magnet. Measuring commuting activity is a challenge as a wide variety of people visit the city for many different reasons. The interdependence of the Northeast mega-region also adds to the complexity.
New York-Newark-Jersey City is such a big cutting cake, that four of the country’s 11 metropolitan divisions (as indicated by the italicized text and the dotted lines) are in that one area.
Blur the lines
Population models are constantly changing across the country, so the next version of this map may feature a number of changes. Our “simple” example of the Texas triangle may become more difficult to divide as the population boom continues in the region.
Here’s how the population of American countries has changed over the past decade:
Complicating matters further is the rapid shift to remote work and distributed teams. Commuting links are a key feature of these census divisions. As the work is increasingly limited by geographic limitations, it is still unclear how this trend will impact this type of statistical exercise in the future.