Denver’s tiniest zip codes, and why they exist

Some of these buildings have their own zip code. (Kevin J. Beaty/Denverite)

If you’ve ever zoomed in on a map of downtown Denver, and I mean really zoomed in, you may have noticed four very small zip codes.

Why do they exist? Well, as USPS Colorado Spokesperson David Rupert explains…

“Zip codes are used to sort mail. That’s it.”

And when they get this small, it’s because the post office decided at some point that it was necessary to create a separate zip code for the area, often because it gets large amounts of mail.

Across the country, there are about 21,000 of these large mailers — companies, military installations and universities with their own zip code.

“As long as operationally it still works for us, there would be no need to blend it somewhere else,” Rupert said. “There’s a lot of room to grow in within a zip code or to reduce. Generally, there’s not a need to take back a zip code. ”

In fact, the post office issues 30 new zip codes a year. Many of them end up in the West and Southwest, Rupert says, because that part of the country grows more than it infills.