Editing ZIP Code (section)

=== Division and reallocation ===
Like [[Telephone numbering plan|area code]]s, ZIP Codes are sometimes divided and changed, especially when a [[rural]] area becomes [[suburb]]an. Typically, the new codes become effective once announced, and a grace period (e.g., one year) is provided in which the new and old codes are used concurrently so that postal patrons in the affected area can notify correspondents, order new stationery, etc.<ref>{{cite news |first=Sam |last=Roberts |url=https://www.nytimes.com/2007/03/21/nyregion/21zip.html |title=An Elite ZIP Code Becomes Harder to Crack |work=[[The New York Times]] |date=March 21, 2007 |page=C15 |access-date=July 10, 2009 |archive-date=January 26, 2021 |archive-url=https://web.archive.org/web/20210126211652/http://www.nytimes.com/2007/03/21/nyregion/21zip.html |url-status=live }}</ref>

Opening a new sectional center facility is sometimes necessary in rapidly growing communities, which must then be allocated three-digit ZIP-code prefixes. Such allocation can be done in various ways. For example, when a new sectional center facility was opened at [[Washington Dulles International Airport|Dulles Airport]] in Virginia, the prefix 201 was allocated to that facility; therefore, for all post offices to be served by that sectional center facility the ZIP Code changed from an old code beginning with 220 or 221 to a new code or codes starting with 201. However, no new prefix was assigned when a new sectional center facility was opened to serve [[Montgomery County, Maryland]]. Instead, ZIP Codes in the 207 and 208 ranges, which had previously been assigned alphabetically, were reshuffled so that 207xx ZIP Codes in the county were changed to 208xx codes, while 208xx codes outside that county were changed to 207xx codes. Because [[Silver Spring, Maryland|Silver Spring]] (whose postal area includes [[Wheaton, Maryland|Wheaton]]) has its own prefix, 209, there was no need to apply the reshuffling to Silver Spring; instead, all mail going to 209xx ZIP Codes was simply rerouted to the new sectional center facility.

On the other hand, [[depopulation]] may cause a post office to close and its associated ZIP Code to be deallocated. For example, [[Centralia, Pennsylvania]]'s ZIP Code, 17927, was retired in 2002,<ref>{{cite news |first=Rob |last=Wheary |url=http://www.centraliapa.com/news.htm |title=Centralia loses its ZIP |access-date=2010-05-02 |archive-date=2012-03-24 |archive-url=https://web.archive.org/web/20120324201418/http://www.centraliapa.com/news.htm |url-status=dead }}</ref> and ZIP Codes for [[Onoville, New York|Onoville]] (14764), [[Elko, New York|Quaker Bridge]] (14771) and [[Red House, New York|Red House]] (14773) in New York were prevented from going into use in 1964 in preparation for the [[Kinzua Dam]]'s completion.<ref name=postofficesclose>{{cite news|title=Post Offices to Close|newspaper=The Bradford Era|date=April 22, 1964}}</ref><ref>{{cite news|title=Final Check-Out|newspaper=Salamanca Republican-Press|date=July 1, 1964}}</ref>