On the website of the U.S. Postal Service, you can find nine-digit zip codes. There is a way to find a zip code under “Quick Tools.” It asks the user to type in their address and then finds their USPS ZIP+4 code.
ZIP stands for “zone improvement plan.” It was put into place in the United States in 1963 to organise and improve the postal system. The first three numbers of the original five-digit zip code indicate the sectional centre facility, which is a central processing facility. The last two numbers tell you which post office the address is for. In the 1980s, the last four digits were added to give a more detailed description of where the zip code is.
