Theoretical physicist Dirk Brockmann used the dollar bill tracking site Where’s George to see how money moves, and create new state boundaries based on our economies. The darker the blue lines, the less likely it is a dollar bill will have crossed it.

The Northwest is one large state.

California takes over parts of Nevada and all of Arizona.

The southwest and mountain west are one nebulous region, with some slightly less solid internal boundaries.

All of the upper midwest is one unit.

A new state is created around the Ozarks (though Missouri has a distinct east/west boundary); Texas remains more or less intact.

The area around Chicago becomes one large state.

The entire deep south is also joined together.

New England becomes one unit, effectively walled off from New York.

New England becomes one unit, effectively walled off from New York.

New England becomes one unit, effectively walled off from New York.

New England becomes one unit, effectively walled off from New York.

New England becomes one unit, effectively walled off from New York.


A New Map Of The U.S., Created By How Our Dollar Bills Move

Using a site that tracks dollar bills, a theoretical physicist noticed that our state boundaries are rather arbitrary, but that money tends to stay within new, more realistic boundaries.

To theoretical physicist Dirk Brockmann, the borders of the United States are out of date.

"Some are kind of arbitrary like New Mexico, Arizona: They’re just kind of drawn on the map," says Brockmann. "Often, they no longer correlate with our behavior."

Specifically, they no longer correlate with how we move.

Brockmann was doing research on human mobility in 2005, and struggling to find useful sources of data, when on the way back from a conference in Canada, he stopped by the home of his old friend Dennis Derryberry in the Green Mountains of Vermont. Over a beer on the porch, he told Derryberry about his research. Derryberry asked: "Do you know about"

You can think of as a primitive FourSquare for $1 bills. "Georgers"—as users call themselves—"check in" their bills by entering the zip codes and serial numbers, then write or stamp "" on the bill. If someone finds the bill and enters it again, they get a "hit." The top Georger—an ammunition dealer who goes by the handle Wattsburg Gary—has entered more than 2 million bills and has nearly half a million hits.

This was, according to Brockmann’s account, the beginning of "Where’s George?" research: "Forming a mental image of millions of these dollar bill journeys in my head, I was convinced that analyzing this data would reveal essential properties of human mobility, the driving force behind the dispersal of bank notes."

Brockmann has, in fact, used the dollar bill data to reveal certain "essential properties" (specifically, that our travels follow a Power Law), and also to model the Swine Flu epidemic. But one of his coolest research projects is his work on "effective boundaries."

Brockmann took data for how the dollar bills traveled, and used network theory to draw lines where dollar bills are less likely to cross. In places they follow state borders, but not always; Missouri is divided into East and West, as is Pennsylvania. The "Chicago catchment area" includes a big chunk of both Indiana and Wisconsin.

The resulting map shows how "effective communities" don’t necessarily follow state lines. "I don’t know so much about the culture of the U.S.," says Brockmann, who grew up in Germany. "But when I give talks on this, normally someone in the audience says, 'Oh, this makes perfect sense."

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  • David Lee

    I think the aggregation of these virtual States really resembles the Federal Reserve districts.

  • david mills

    I love having the fifty states, I would hate for people or to try to change things around because they think whats best for other people, Ideas of our country are getting screwed up because people are medeling where they really have no understanding how laws and economics work to help keep us a free nation, look at Obama care, I had heard that it's gonna leave the poor with out any health care.  I thought I heard between 10 million to 20 million people it was on the news radio, not a talk radio show but the news you get every half hour. They lied about how it was gonna cover everybody it was just a scam for the drug companies. Let's not change the states of this country it's the wrong thing for us all, the government and thugs in congress and the white house would love us to lose our control over them. quit changing things! If you are a progressive, are things progressing better or are they progressively getting worse? I say worse and don't think much of the bushes neither just more progressives.

  • BurtAllen

     I'll bet you're great at gatherings where people are trying to have a conversation.

  • Skatt

    It's not just the Fed reserve districts. It is also a reflection of how, over time, the states have lost independence and become more of an extension of the federal govmt.

  • elmo_fud

    When looking at the flow of currency in the US it will be Federal Reserve District that governs movement, not state boundaries. State borders as boundaries to currency movement would have disappeared with the Articles of Confederation.

    At least based on visual inspection, his boundaries seem to correlate reasonably well with FRD boundaries - see

  • John

    The map is wrong. Dollars travel from Chicago to points north like Escanaba, MI , Marquette, MI...Your map shows the dollars going from Nowhere, IA to what? Ashland WI?

  • Skatt

    This is called projecting averages. It is as much about quantity as quality. This data was obtained through actual work, not sitting at a computer and sharing an option about what he thinks is happening.

  • SocraticGadfly

    What it is, to some degree, is a map of Federal Reserve districts, though not totally. So .. big deal?

  • Bombthrower77

    Agree completely and since Fed Districts distribute currency ("Georges" still have district seals), this seems like a spurious correlation missed by a physicist who has "discovered" economics......

  • Don

    I don't think this is such a meaningful measure of human activity, since it only relates to paper money migration. Most modern commerce does not use paper money, so all the credit card and online transactions are ignored, not to mention payment by checks. It is somewhat interesting, but I don't think it can be used as the basis for any policy making.

  • D R Allen

     (this is actually a response to the reply from "Dan")

    Actually, it is NOT "a measure of human mobility" either - it's only a measure of the mobility of the VERY small subset of humans who take the time to enter information into a specific website after seeing that someone has written something on a dollar bill.

    It doesn't include dollars transported by busy people who don't waste a lot of time reading their cash, (much less take the time to enter numbers into a website), it doesn't include the number of people who use $5, $10, and $20 bills (and lots of coins) for just about everything (to the point that Treasury frequently discusses discontinuing the $1 bill due to its lack of use and expense of production), it doesn't include people who use credit/debit cards to purchase EVERYTHING, and it doesn't reflect that all of those dollar bills going into vending/change machines are bundled up in large bricks of cash and transported elsewhere.

    No, it is a pretty poor proxy for HUMAN mobility, and not an especially good one for that of cash either.

    If you want to see where humans travel, I'd suggest tracking the movement of their mobile phones. In 21st Century America, almost NO one leaves their homes w/out one (what few elderly citizens that mey not have one either stay at home, or are driven by a younger person who DOES have one), and they are easily tracked by existing computer apps/software (despite crime/spy entertainment to the contrary, not many people travel w/their phones disabled).

  • Dan

     You miss the point entirely.  It's not a measure of all human activity, it's a measure of human mobility.  The flow of non-cash transactions have absolutely nothing to do with human mobility.  The point is the dollar bill (and other denominations) acts as a proxy of how humans TRAVEL.  There currently is no better data source that really can explain how humans travel, regardless of method (air, car, train, foot, etc).

  • pbrower2a

    Maybe the $1 bills don't travel as far as bigger bills. A dollar bill just doesn't buy much. People rarely use dollar bills to go long distances. Big cash purchases might use twenties or fifties, though.

    The money in a greeting card "Couldn't think of what to send you, but I'm sending Ben (Franklin) for company!" might be mailed across the country. At that you might take big bills to an out-of-state tourist trap.

  • juandos

    Why is it unforntunate that money was the motivator?

    Money motivates most everything...

  • Joyce

    Lake Champlain "walls off" Vermont from New York, and the people & money in CT flow north and south, rather than east and west. Western CT is surprisingly rural.  Much of this can be explained by geographic features, such as waterways with limited bridges (Champlain, Connecticut and Mississippi Rivers, for example), and large cities acting as sinks for people & money.

  • Loganjvickery

    I think Stan is ignoring some lines there...  His Deep South is not a well defined singular unit for example.  It looks like South Carolina is more likely in a state with New York than Georgia.

    Great find though!

  • Dirk Gentley

    Maybe that is because of all the Yankees travelling to S.C. for the beach?