ZIP Code geeks

[english si]

There's an entire page (with maps) on Wikipedia for all 121 UK postcode areas describing where all the postcode districts are (and normally little else).

Eg https://en.wikipedia.org/wiki/LD_postcode_area

This kind of reference book trivia is exactly what Wikipedia is both best suited to and what it does best. It would be silly to purge it.

[DTComposer]

Don't think this has been mentioned: In many larger cities, the last two digits of a zip code correspond to their postal district zone from the pre zip-code days. For example:

Los Angeles 27, Calif.
became
Los Angeles, CA 90027

[minneha]

Wikipedia used to have a really excellent ZIP code chart, but it was destroyed by the deletionist mafia.

https://web.archive.org/web/20241126195036/https://en.wikipedia.org/wiki/List_of_ZIP_Code_prefixes

I agree, that's a really excellent ZIP Code chart. It's a shame that it's not on Wikipedia anymore.

I really appreciate the logic of the ZIP Code numbering process. Most people probably don't realize that the first number in a ZIP Code indicates a group of states to which that state belongs. The first two numbers taken together are unique to that particular state. And the first three numbers taken together represent geographic regions within that state. That chart makes it very intuitive to understand.

It looks like some prefixes near more populated cities were deliberately unused, perhaps so there would be more prefixes to use if those cities or suburbs outgrew their main prefix? Like in Kansas City, Missouri, 641 is the main ZIP Code, but 642 and 643 are unused. And on the Kansas side suburbs, 662 is the main ZIP Code and 663 is unused.

In Omaha, 681 is the main ZIP Code and 682 is unused.

In Oklahoma City, 731 is the main ZIP Code and 732 is unused.

In Tulsa, 741 is the main ZIP Code and 742 is unused.

Even in Springfield, MO, 658 is the main ZIP Code and 659 is unused.

Interestingly, they did not do this in Wichita. Wichita is 672, but there is no unused prefix in the 67 series.

I find the Liberal, KS 679 ZIP Code region to be peculiar. It only exists in three counties and only has 7 ZIP Codes, two of which are in Liberal itself, one ZIP Code for the city and another ZIP Code for P.O. Boxes. I wonder why this region was not made part of the Dodge City 678 region.

Here's a good site that has a lot of accurate information about ZIP Codes:

https://www.unitedstateszipcodes.org/

[Road Hog]

Celina, TX will need a second ZIP code in a very short time. Its current post office was built when the city had a population of 2,000 and already it's almost maxed out.

The current ZIP code is 75009, but the city of Carrollton (originally 75008) has already laid claim to 75010 and 75011, so the next ZIP code available for Celina will be 75012.

[kernals12]

Here's a fun fact, the abbreviated code for Nebraska used to be NB. In 1969, they changed it to NE to avoid confusion with the province of New Brunswick in Canada.

[bassoon1986]

Ok here's another zip code geeky thing to find. What is the greatest numerical difference between two bordering zip codes? Because some states have pretty radical differences in regions. I always thought it was crazy that

A) Louisiana was in a district beginning with 7. Being nearly in the southeast, it seemed odd when most of the western US begins with 8 or 9.

B) Louisiana begins with 7, and neighboring Mississippi begins with 3


This is the best I've found:
72395 - Wilson, AR
borders
38015 -Gilt Edge, TN

A difference of 34380

[6a]

Schenectady has the stupidest ZIP Code I've ever heard of in my life! That's the kinda thing an idiot would have on his luggage!

If you're talking about 12345, that's not really Schenectady. And it is sort of a pride thing for those guys.

On the flip side, the area around Ohio State is 43210.

[bing101]

9-xxxx
9 the first digit for the West Coast.
90 and 91 are the second digits for Los Angeles County Specifically.

92 is for other parts of Southern
California

93 for Central California

94 for San Francisco Bay Area
95 Sacramento and California delta area
96 Northern California

97
98
99

[DTComposer]

9-xxxx
9 the first digit for the West Coast.
90 and 91 are the second digits for Los Angeles County Specifically.

92 is for other parts of Southern
California

93 for Central California

94 for San Francisco Bay Area
95 Sacramento area
96 Northern California

97
98
99

Kinda - here's a little more detail:

90 - Los Angeles County (southwestern section)
91 - Los Angeles County (central section)
92 - San Diego, Orange, San Bernardino, Riverside Counties
93 - Central California (including Fresno, Bakersfield, and Santa Barbara)
94 - Central and north Bay Area (including San Francisco and Oakland)
95 - South Bay Area, northern coast and Central Valley (including San Jose and Sacramento)
96 - Northern mountains, Hawaii, Pacific territories, Pacific military bases
97 - Oregon
98 - (most of) Washington
99 - Eastern Washington, Alaska

[Road Hog]

Ok here's another zip code geeky thing to find. What is the greatest numerical difference between two bordering zip codes? Because some states have pretty radical differences in regions. I always thought it was crazy that

A) Louisiana was in a district beginning with 7. Being nearly in the southeast, it seemed odd when most of the western US begins with 8 or 9.

B) Louisiana begins with 7, and neighboring Mississippi begins with 3


This is the best I've found:
72395 - Wilson, AR
borders
38015 -Gilt Edge, TN

A difference of 34380

"Borders" since the only way to access one from the other is to either drive 2 hours via Memphis or boat across the river.

[bassoon1986]

Ok here's another zip code geeky thing to find. What is the greatest numerical difference between two bordering zip codes? Because some states have pretty radical differences in regions. I always thought it was crazy that

A) Louisiana was in a district beginning with 7. Being nearly in the southeast, it seemed odd when most of the western US begins with 8 or 9.

B) Louisiana begins with 7, and neighboring Mississippi begins with 3


This is the best I've found:
72395 - Wilson, AR
borders
38015 -Gilt Edge, TN

A difference of 34380

"Borders" since the only way to access one from the other is to either drive 2 hours via Memphis or boat across the river.

Well, that'll be most counties on either side of the MS River south of the Ohio 🤷🏼�♂️

[kalvado]

Ok here's another zip code geeky thing to find. What is the greatest numerical difference between two bordering zip codes? Because some states have pretty radical differences in regions. I always thought it was crazy that

A) Louisiana was in a district beginning with 7. Being nearly in the southeast, it seemed odd when most of the western US begins with 8 or 9.

B) Louisiana begins with 7, and neighboring Mississippi begins with 3


This is the best I've found:
72395 - Wilson, AR
borders
38015 -Gilt Edge, TN

A difference of 34380

"Borders" since the only way to access one from the other is to either drive 2 hours via Memphis or boat across the river.

Well, that'll be most counties on either side of the MS River south of the Ohio 🤷🏼�♂️

Not as impressive, but Helena, AR 72342 is a short drive from Dundee, MS 38626 for a change of 33716

[TheCatalyst31]

Ok here's another zip code geeky thing to find. What is the greatest numerical difference between two bordering zip codes? Because some states have pretty radical differences in regions. I always thought it was crazy that

A) Louisiana was in a district beginning with 7. Being nearly in the southeast, it seemed odd when most of the western US begins with 8 or 9.

B) Louisiana begins with 7, and neighboring Mississippi begins with 3


This is the best I've found:
72395 - Wilson, AR
borders
38015 -Gilt Edge, TN

A difference of 34380

"Borders" since the only way to access one from the other is to either drive 2 hours via Memphis or boat across the river.

Well, that'll be most counties on either side of the MS River south of the Ohio 🤷🏼�♂️

Not as impressive, but Helena, AR 72342 is a short drive from Dundee, MS 38626 for a change of 33716

It's not directly bordering, but Metaline Falls, WA 99153 borders Bonners Ferry, ID 83805, which in turn borders Troy, MT 59935. That's a difference of 39218 with only one ZIP code in between.

[CNGL-Leudimin]

Other countries, such as Spain, France, Italy and Germany, also use 5 digit post codes. In the case of France, the first two digits always match the department number (save for Corsica, which uses 20 through the entire island), and the fact Alpes de Haute Provence (department no. 04) borders Vaucluse (department no. 84) produce differences over 80000. Germany can have differences over 93000, thanks to post codes starting with 06 (covering most of southern Saxony Anhalt, as well as the area around Artern in Thuringia) abuting those starting with 99 (covering most of northern Thuringia).

[ErmineNotyours]

I never paid much attention to Zip Codes until I worked for the Post Office.  Then I realized as most here have pointed out that the last two digits were assigned mostly alphabetically.  At least that's the case in the 980 Sectional Center, which is King County outside of Seattle.

Where I worked I saw a lot of mail intended for Monaco, the small country next to France.  They also have a five digit numerical code, and all their codes start with 980.  Even worse, I saw some international Monaco mail that was sent to Seattle, which means at least two people didn't look at the whole address before sending the package along.  It took the long way around.

[NWI_Irish96]

I'm not sure this is still the case though I'm guessing that it is, but I know there were places near the Mississippi River in Iowa that had their mail delivered from a PO in Illinois and therefore had an Illinois ZIP code.

[english si]

Where I worked I saw a lot of mail intended for Monaco, the small country next to France.  They also have a five digit numerical code, and all their codes start with 980.

I'm surprised they got 980 in the French system. 01-95 covers Metropolitan France+Corsica. 96xxx isn't used and then 97 is for Overseas Départements and Collectivities

• Guadeloupe - 971
• Martinique - 972
• French Guiana - 973
• Réunion - 974
• Saint-Pierre and Miquelon - 975
• Mayotte - 976
• Saint Barthélemy - 977
• Saint Martin - 978

With 98xxx being used for Overseas Territories.

• French Southern Territories - 984
• Wallis and Futuna - 986
• French Polynesia - 987
• New Caledonia - 988

So is Monaco an Overseas Territory?

[vdeane]

96xxx isn't used

What is it reserved for?

[english si]

96xxx isn't used

What is it reserved for?

It was previously used for somewhere in North Africa (the Protectorate of Morocco?), but unlike the 91xxx-95xxx codes also used in Africa until those countries gained independence, they didn't reuse it for new departments created in Metropolitan France by splitting previous ones*. Instead, the creation of a 96th Metropolitan Department by splitting Corsica into two in 1978, led to 20 remaining the postcodes, and 2A and 2B being the department codes.

*75 Seine and 78 Seine-et-Oise becoming 75 Paris, 78 Yvelines, 91 Essone, 92 Hauts-de-Seine, 93 Seine-Saint-Denis, 94 Val-de-Marne and 95 Val-d'Oise.

[vdeane]

96xxx isn't used

What is it reserved for?

It was previously used for somewhere in North Africa (the Protectorate of Morocco?), but unlike the 91xxx-95xxx codes also used in Africa until those countries gained independence, they didn't reuse it for new departments created in Metropolitan France by splitting previous ones*. Instead, the creation of a 96th Metropolitan Department by splitting Corsica into two in 1978, led to 20 remaining the postcodes, and 2A and 2B being the department codes.

*75 Seine and 78 Seine-et-Oise becoming 75 Paris, 78 Yvelines, 91 Essone, 92 Hauts-de-Seine, 93 Seine-Saint-Denis, 94 Val-de-Marne and 95 Val-d'Oise.

My guess would be Algeria (which was fully part of France for a while).

[english si]

96xxx isn't used

What is it reserved for?

It was previously used for somewhere in North Africa (the Protectorate of Morocco?), but unlike the 91xxx-95xxx codes also used in Africa until those countries gained independence, they didn't reuse it for new departments created in Metropolitan France by splitting previous ones*. Instead, the creation of a 96th Metropolitan Department by splitting Corsica into two in 1978, led to 20 remaining the postcodes, and 2A and 2B being the department codes.

*75 Seine and 78 Seine-et-Oise becoming 75 Paris, 78 Yvelines, 91 Essone, 92 Hauts-de-Seine, 93 Seine-Saint-Denis, 94 Val-de-Marne and 95 Val-d'Oise.

My guess would be Algeria (which was fully part of France for a while).

that would be a bad guess as Algeria was definitely 91-93. Tunisia and Morocco had postal codes in the 94-96 range and I gather the order was Tunisia first, but didn't find anything proving it.