To make this more than "this is just the xkcd population map joke" https://xkcd.com/1138/ , better title could be "Distribution Search of Zip Codes in the United States".

Point here is to type 0, 1, 2, etc. in the search box to see how zip codes with that prefix are geographically distributed.

I read an interesting story where this distribution comes from the manual mail sorting days... before computer sorting, postal workers could read the first digit and drop it into one of 10 boxes based on what part of the country it was going to, and so on for each additional digit.

Other countries have said "ah f it, it's all computers these days anyways, lets just make all addresses arbitrary random codes with no correlation between code distance and geographic distance. A database lookup at computer speed is a database lookup no matter what."