41,683 zip codes in the US Postal system

I've been working on some updates and including more and more data into the project. So much to do and learn! To be honest, the more I learn about how the USPS works, the more impressed I am.

To date, I've mailed out more than 3,000 letters and stickers for this project and plotting them on the map. When the project started, it was just a few hundred. With the growth of the project, I need to improve my work flow and data management.  For this project, that means zip codes!

There are USPS 41,683 zipcodes!

Check out the map on this info page: https://facts.usps.com/42000-zip-codes/

I knew that the first three numbers in the zip code indicated which sorting center a letter passed through. But now I've learned that the first number refers to multi state regions.  I'm having flash-backs to sorting algorithms from my CS grad school days...seeing binary sorting trees, but 9 instead of 2...and how physical sorting got worked out.