Here’s a fun map, made by New York-based information visualization expert (and cartoonist) Dorothy Gambrell, showing “peak state.” In other words, according to the US census, it shows the decade at which each state contained the peak percentage of the US population.
It’s a fun map. Some of the things that catch my eye are the general Westward expansion and the recent dominance of the western states. (Note that the “peak state” years of the old South remain firmly in the 19th century.)
Also very strange? Michigan. Detroit had a very late population growth spike, in the 1920s to the 1950s, and then cratered in a typical “boomtown” fashion. Also the line between Montana (1920) and Idaho (2010) is sort of interesting.
Meanwhile, Minnesota peaked as a percentage of the US in 1900, alongside neighboring Wisconsin. This might be one reason why Minnesota is likely to lose a congressional district in the next census reallocation.