. . . but something I just learned is that area codes were originally assigned according to the population density of the city or region, with the lowest numbers going to the most populous areas. Keeping in mind that phones in those days had rotary dials, and higher numbers therefore took longer to dial, the thinking was that areas with the most people should be the easiest to call.
That’s why New York City got area code 212, Chicago got 312, Los Angeles got 213, etc. (Zero actually counts as a high number — a 10, essentially — because it takes the longest to dial.)
Conversely, the area code for the entire state of Alaska was (and still is) 907.