What Happened to the American Boomtown?

Chicago in 1850 was a muddy frontier town of barely 30,000 people. Within two decades, it was 10 times that size. Within another two decades, that number had tripled. By 1910, Chicago — hog butcher for the world, headquarters of Montgomery Ward, the nerve center of the nation’s rail network — had more than two million residents.

“You see these numbers, and they just look fake,” said David Schleicher, a law professor at Yale who writes on urban development and land use. Chicago heading into the 20th century was the fastest-growing city America has ever seen. It was a classic metropolitan magnet, attracting anyone in need of a job or a raise.

But while other cities have played this role through history — enabling people who were geographically mobile to become economically mobile, too — migration patterns like the one that fed Chicago have broken down in today’s America. Interstate mobility nationwide has slowed over the last 30 years. But, more specifically and of greater concern, migration has stalled in the very places with the most opportunity.