This map shows all the metropolitan areas in the US

The United States is the third most populous country in the world, made up of close to 20,000 cities and towns, and 333 million individuals.

Dividing these population clusters into a coherent framework of statistical areas is no small feat, and the US Census Bureau’s latest map shows just how complex of a task it is.

This enormous map—which covers the entire country, including Puerto Rico—includes 392 metropolitan statistical areas and 547 micropolitan statistical areas.

For reference, here are all the current metropolitan statistical areas in the United States, organized by population:

For the full interactive list, click here.

The wide variety of population patterns around the country can make it tricky to divide regions up into uniform units. There are two main divisions to consider when viewing this map:

Metropolitan Areas (metro areas) have at least one urban core area of at least 50,000 population. These are the largest population centers, sometimes encompassing many counties. In some instances, these metro 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 away from large cities, have at least one urban core area of at least 10,000 but fewer than 50,000 people.

One thing to note about all of these definitions is that the cities in these regions must have significant ties to a neighboring region—usually in the form of commuting ties. This is what warrants binding adjacent counties into a measurable area.

Another unique layer of data on this map is the shading that indicates the actual urbanized area within metro areas. In the example of Atlanta-Sandy Springs-Alpharetta, it’s easy to see how urban sprawl has expanded the urban area into a number of neighboring counties.

With this context in mind, 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.

The Texas Triangle offers what is perhaps the most straightforward example of metro areas.

As seen above, Houston, Austin, and San Antonio anchor their respective regions, and surrounding counties are bundled into a metro area. The surrounding counties have all been identified as having ties to the central county, and, in some cases, the urban area has spread into the neighboring county over time.

The region anchored by Salt Lake City requires more thought to divide into statistical areas.

While there are a number of population centers in the area, including Salt Lake City, Provo, and Ogden, they all have enough of an economic “magnetic pull” to warrant splitting the region into distinct statistical areas.

Of course, regions are always evolving, and occasionally these areas are updated. Salt Lake City and Ogden were previously combined into a single metro area, but were separated in 2005.

New York City is the ultimate challenge for planners looking to categorize population centers into a neat and tidy statistical box.

For one, the contiguous urban area is massive, stretching from the west side of Long Island out to the east side of New Jersey. In addition to New York City itself, the metro area includes 19 other municipalities with over 100,000 people.

Next, NYC is an unparalleled economic magnet. Measuring commuting activity is a challenge because a wide variety of people visit the city for so many different reasons. The interconnectedness of the Northeast Megaregion also adds to the complexity.

New York-Newark-Jersey City is such a big pie to carve up, that four of the country’s 11 metro divisions (as indicated by the italicized text and dotted lines) occur in this one area.

Population patterns are constantly changing across the country, so the next version of this map may have a number of changes on it. Our “straightforward” Texas Triangle example may become tougher to divide up as the population boom continues in the region.

Here’s how the population of US counties changed over the past decade:

Further complicating matters is the rapid move to remote work and distributed teams. A key element of these census divisions are commuting ties. With work increasingly not bound by geographic limitations, it remains unclear how that trend will impact this type of statistical exercise in the future.