Rising and ebbing

An interesting way of visualizing the changing fortunes of American cities is at this graph of metropolitan population ranks over time, compiled by Greg Slayden. Some notable trends:
– The most “turbulent” periods appear to be the western settlement in 1820-1860 and the rise of the Sunbelt in 1970-1990
– Dramatic movements appear just as often as stable oscillations, particularly when cities appear or disappear from the list
– The only city that appears on the Top 20 list, disappears, then makes a comeback appears to be Seattle

Might be interesting to group the cities — say, regionally, to see the rise of different parts of the country.