Tuesday, September 6, 2016


When we were first informed that Monrovia’s very own ZIP Day is right around the corner on September 10, 2016.  Our reaction was “What is ZIP day?”  

9-10-16...Oh, then we got excited...really excited.  Really, no really...

ZIP Day is a once in a lifetime celebration of our zip code—9.10.16.   Since zip codes didn’t exist until 1963, there was no ZIP day in 1916—and with the rapid changes occurring in the way people communicate, there is no promise that zip codes will still exist in 2116. 

So let's start with the basics...how did zip codes come into use?   Many people have seen antique letters or postcards simply addressed to Joe Smith, Monrovia, Calif. 

This harkened to a simpler time when residents had to visit the post office to pick up their mail, which had likely been sorted alphabetically by name.  In 1911, Monrovia considered having free mail delivery—meaning a postal worker would deliver the mail to each residence.   This meant that mail would needed to be sorted by address, so street names and house numbers began to appear on envelopes.   Letters were still the main method of communication, so imagine the volume that needed to be sorted daily.

In 1944, with World War II increasing the number of letters sent while the work force to sort the mail was diminished, a postal inspector named Robert Moon thought up a new system which would speed up sorting.  He promoted a numerical system in which the first three digits identified the geographic area and the Sectional Center Facility (SCF) that would receive all the mail for a specific geographic area and then the last two digits would specify a particular city in that geographic region.   The post office named this system the Zone Improvement Plan (ZIP)  It took almost twenty years for the US Postal Service to roll out zip codes—zip codes were officially introduced on 7/1/1963 and at the same time the Post Office encouraged standardized two letter abbreviations for states.

The post office used many different ways to make people aware of zip code use.  They introduced a cartoon character named Mr. Zip who was featured in commercials, cartoons, on merchandise such as stickers and lunch boxes, and appeared on stamp cancellations. The Post Office believed that if they could get children to be interested in Mr. Zip, they, in turn, would encourage their parents to use zip codes.  In 1966, the week of October 10 was officially declared “Zip Code Week” with some communities holding parades to celebrate.   Celebrities such as Ethel Merman appeared on commercials singing “Zip–a–dee–do-dah”.    In reaction to Cold War paranoia, some citizens protested the use of zip codes as dehumanizing, but the popularity of Mr. Zip outweighed these worries.  By 1970 zip codes were used on 86% of the mail and by 1979 they were on 97% of all mail. 

In 1983, the US Post Office promoted a new Zip+4 program, though they have never made it mandatory. 

Zip Codes are made up of three components: geographic region, Sectional Center Facility (SCF), and the town, city or community.  Numbers were distributed from East to West.  Zip Codes beginning with zero are generally in New England and New Jersey.  The lowest zip code is 00501 for the IRS in Holtsville, NY.   The highest zip code is 99950 for Ketchikan, Alaska. 

So here's what those numbers in Monrovia’s zip code stand for:
  • 9- California (also HI, AK, OR, WA and Pacific territories)
  • (9)10—Santa Clarita is Monrovia’s SCF (Sectional Center Facility)
  • (910)16 – Monrovia
  • (910)17- Monrovia’s PO boxes

So, here's one last piece of Monrovia zip code trivia: did you know that our zip code is an ambigram?  That is, it’s the same number if you turn it upside down!  Not many zip codes can make that claim to fame.

So checkout this page to celebrate this once in a lifetime event.