Editing ZIP Code (section)

=== Establishment ===
By the early 1960s, a more organized system was needed. Non-mandatory five-digit ZIP Codes were introduced nationwide on July 1, 1963.<ref name=mlcdintr/><ref name=lblsccs/> The USPOD issued its ''Publication 59: Abbreviations for Use with ZIP Code'' on October 1, 1963, with the list of [[List of U.S. state abbreviations|two-letter state abbreviations]] which are generally written with both letters capitalized.<ref name=USPS>[https://about.usps.com/who-we-are/postal-history/state-abbreviations.pdf "State Abbreviations", USPS.com] {{Webarchive|url=https://web.archive.org/web/20170116005935/http://about.usps.com/who-we-are/postal-history/state-abbreviations.pdf |date=2017-01-16 }}.</ref> An earlier list, publicized in June 1963, had proposed capitalized abbreviations ranging from two to five letters.<ref name=USPS/> According to ''Publication 59'', the two-letter standard was "based on a maximum 23-position line, because this has
been found to be the most universally acceptable line capacity basis for major addressing systems",<ref name=USPS/> which would be exceeded by a long city name combined with a multi-letter state abbreviation, such as "Sacramento, Calif." along with the ZIP Code. The abbreviations have remained unchanged, except for [[Nebraska]], which was changed from NB to NE in 1969 at the request of the [[Canada Post|Canada Post Corporation]], to avoid confusion with [[New Brunswick]].<ref name=USPS/>

[[Robert Moon (postal inspector)|Robert Moon]] is considered the father of the ZIP Code; he submitted his proposal in 1944 while working as a [[United States Postal Inspection Service|postal inspector]].<ref>Bullamore, Tim (2001). Robert Moon Obituary. Retrieved from https://www.independent.co.uk/news/obituaries/robert-moon-729034.html {{dead link|date=December 2019}}.</ref><ref>{{cite news | url = https://www.nytimes.com/2001/04/14/us/robert-moon-an-inventor-of-the-zip-code-dies-at-83.html | title = Robert Moon, an Inventor of the ZIP Code, Dies at 83 | first = Douglas | last = Martin | date = 2001-04-14 | newspaper = [[New York Times]] | access-date = 2017-09-23 | archive-date = February 17, 2020 | archive-url = https://web.archive.org/web/20200217102920/https://www.nytimes.com/2001/04/14/us/robert-moon-an-inventor-of-the-zip-code-dies-at-83.html | url-status = live }}</ref> 

The phrase "zone improvement plan" is credited to [[D. Jamison Cain]], a Postal Service executive.<ref name="cain">{{Cite news |url=https://www.washingtonpost.com/local/virginia-resident-pushed-the-envelope-when-zip-code-was-born-in-1963/2018/09/29/38376e7a-c28c-11e8-97a5-ab1e46bb3bc7_story.html |title=Virginia resident pushed the envelope when Zip code was born in 1963 |date=2018-09-29 |last=Kelly |first=John |newspaper=[[The Washington Post]] |access-date=2022-08-13 |archive-date=October 10, 2018 |archive-url=https://web.archive.org/web/20181010205600/https://www.washingtonpost.com/local/virginia-resident-pushed-the-envelope-when-zip-code-was-born-in-1963/2018/09/29/38376e7a-c28c-11e8-97a5-ab1e46bb3bc7_story.html |url-status=live }}</ref> The post office credits Moon with only the first three digits of the ZIP Code, which describe the [[sectional center facility]] (SCF) or "sec center". An SCF is a central mail processing facility with those three digits. The fourth and fifth digits, which give a more precise locale within the SCF, were proposed by Henry Bentley Hahn Sr.<ref>{{Cite web|url=http://archiveblog.jfklibrary.org/2015/05/papers-of-h-bentley-hahn-the-man-who-invented-the-zip-code/|title=Papers of H. Bentley Hahn: The Man Who Invented the 5-Digit ZIP Code |website=Archivally Speaking |first1=Lauren |last1=Wallace |date= May 15, 2015 |publisher=John F. Kennedy Presidential Library Archives |language=en-US|access-date=2018-04-30|archive-url=https://web.archive.org/web/20180501095121/http://archiveblog.jfklibrary.org/2015/05/papers-of-h-bentley-hahn-the-man-who-invented-the-zip-code/|archive-date=2018-05-01|url-status=dead}}</ref>

The SCF sorts mail to all post offices with those first three digits in their ZIP Codes. The mail is sorted according to the final two digits of the ZIP Code and sent to the corresponding post offices in the early morning. Sectional centers do not deliver mail and are not open to the public, although the building may include a post office that is open to the public, and most of their employees work the [[shift work|night shift]]. Items of mail picked up at post offices are sent to their SCFs in the afternoon, where the mail is sorted overnight. In the case of large cities, the last two digits as assigned generally coincided with the older postal zone number.<ref name=":0" />

For example:

<blockquote>
<poem>
Mr. John Smith
3256 Epiphenomenal Avenue
Minneapolis, MN{{nbsp}}{{nbsp}}554''16''
</poem>
</blockquote>

In 1967, these became mandatory for second- and third-class bulk mailers, and the system was soon adopted generally. The United States Post Office used a [[cartoon]] character, which it called [[Mr. ZIP]], to promote the use of the ZIP Code.<ref name="mrzip">{{Cite web|title=Mr. ZIP- The nation's original 'digital' icon|url=https://about.usps.com/who-we-are/postal-history/mr-zip.pdf|url-status=dead|archive-url=https://web.archive.org/web/20090508223728/https://www.usps.com/postalhistory/_pdf/MrZIP.pdf|archive-date=2009-05-08}}</ref> The name "Mr. ZIP" was coined by D. Jamison Cain.<ref name="cain"/> Mr. ZIP was often depicted with a legend such as "USE ZIP CODE" in the [[selvage]] of panes of [[postage stamp]]s or on the covers of booklet panes of stamps.<ref name="mrzip"/> Mr. ZIP was featured prominently alongside musical group "The Swingin' Six" in a variety show that the post office used to explain the importance of using ZIP Codes.<ref>{{Cite web|date=2013-07-01|title=The US Postal Service's zip code system turns 50|url=https://www.scpr.org/programs/take-two/2013/07/01/32505/the-us-postal-services-zip-code-system-turns-50/|access-date=2020-06-16|website=Southern California Public Radio|archive-date=June 16, 2020|archive-url=https://web.archive.org/web/20200616062613/https://www.scpr.org/programs/take-two/2013/07/01/32505/the-us-postal-services-zip-code-system-turns-50/|url-status=live}}</ref>