In 1790, just a few years into America’s independence, the country’s 10 most populated cities were tightly packed into the Northeast with just one exception (Charleston, South Carolina). Fast-forward 220 years and the U.S. has manifested its destiny more evenly across the continent: just two Northeast cities make the 2010 list, accompanied by the Midwest, Texas, and West Coast. The country’s mean population center has shifted toward the middle of Missouri.
Digital mapmaker Keir Clarke has tracked America’s deliberate westward march in a new interactive viz he calls “Shifting Cities.” Clarke—whose cartographic skills you might remember from this delightfully poisonous Yahoo! “Autocomplete Map” or this psychedelic rendering of Washington, D.C.—delivers the details at his Google Maps Mania blog:
When you select a decade from the slider control the blue markers show the location of the top ten most populated cities and the red marker shows the mean center of the population. The left hand side panel also updates to show a numbered list of the top ten cities for the selected ddecade. The small window in the top right-hand corner of the map also updates to provide more general information on the patterns of population movement being shown on the map.
Clarke used Census data (via Wikipedia) to compile each decade’s top 10 list, as well as the mean center population. Via email he tells CityLab he wanted to combine two previous maps that he enjoyed: a Census animation of the mean center’s slowly trek from Kent County, Maryland, to Texas County, Missouri; and a decade-by-decade animated GIF of the 10 most populated cities. “The animated gif was a little hard to read as you couldn't pause the animation,” he emails. “So I decided to create my own interactive version.”
We screen-grabbed a selection of years as an example. Here’s the original glimpse of 1790:
Here’s a look at 1860, just before the Civil War. Chicago makes its first appearance in the top 10 club, joining Midwest colleagues Cincinnati and St. Louis. With New Orleans pulling some of the population south, the mean has reached Pike County, Ohio.
Now here’s a look 50 years later, in 1910. Pittsburgh and Detroit, on the respective strength of U.S. Steel and Ford Motor Company, make their top 10 debuts. No city west of St. Louis makes the list—San Francisco, on the list since 1870, fell off after the devastating 1906 earthquake—but the general population has moved enough for Monroe County, Indiana, to become the mean center.
And here’s 2010, with a top 10 of New York, L.A., Chicago, Houston, Philadelphia, Phoenix, San Antonio, San Diego, Dallas, and San Jose:
Go West at your own pace, readers.