USPS now offers official ZIP Code boundary polygons

I don't know why the taxpayer should subsidize fintechs.

https://postalpro.usps.com/ZCB_License

>Four quarterly updates with limited publication.

Sharing it with everyone is probably going to get you banned from getting quarterly updates, as there's strings attached. Though I do wonder just how they keep track. Are they fingerprinting the data somehow? Does that make the dataset less useful?

(Or start a gofundme for it.)

https://en.wikipedia.org/wiki/ZIP_Code_Tabulation_Area

It is great for governments to run responsible budgets, but this was such a unique constraint, it seems designed to strangle the USPS.

For a long time it was in this weird double bind because the federal government mandated generous health insurance for USPS employees, but did not allocate funds for it, because USPS was supposed to provide its own funds to cover all expenses. It looks like new legislation (PSRA) was finally passed in 2022 to move that burden from USPS and onto the OPM.

I think the one I enjoyed the most was a zipcode with 38 separate geographical areas, and the other example was a street where one half was one zip code, and the other was a different one, but half way down the street they swapped sides. Representing that with non-overlapping polygons was impossible. So we just let them overlap and shrugged.

Here is an example using Mapbox GL - https://demos.mapbox.com/boundaries-explorer/?country=US&lay...

Imagine a river that divides two zip codes, with river-front property on both sides. If that river has a bend in it (-∿-) that's greater than the width of the river+property, the polygon bounding one zip code would cut through the other, or the polygon is non-convex where it bends along the river.

There has always (since the late 90s) been a free look up webpage:

https://tools.usps.com/zip-code-lookup.htm

The data used to be available on CDROM (back in the 90s) but moved to an API in the early 2000s. Until August 2026, you used to be able to look up addresses for free.

To get the biggest discount on postage (one place I worked at mailed about 3k envelopes per month) you have ZIP+4, to pre-sort the mail and print a bunch of stuff on that barcode [0]. Next time you get an envelope, look at the barcode on the bottom.

https://en.wikipedia.org/wiki/Intelligent_Mail_barcode

0 - doing it that way saved about $450/month versus not doing any of their work for them.

This isn't the USPS charging for existing data. They created a new data set that's only relevant to data brokers, and are charging for it.

it's not that complicated: FedEx and UPS and several other related business types have been trying to kill it for years

the "privatize everything" crowd that would charge you for air if they could.

If you ever wonder why you get so much postal spam, this is why. The USPS is mostly funded by advertising. They could, for instance, stop the practice of accepting "deliver this junk to every mailbox in this region"...but then they'd go bankrupt.

1. Mandate universal delivery of letters regardless of distance or remoteness, even out in some wilderness region of Alaska, guarantee everyone the right to get a letter for the same stamp price as to deliver a letter from one office in the Chrysler Building to another one.

2. Have USPS not get taxpayer funds for anything

3. Impose arbitrary price controls on postage based on Congressional vibes

4. Have postal employees still be federal employees and qualify for cushy benefits and retirement (I assume this is there because their unions would strike if it was taken away)

5. Micromanage how that retirement plan is funded

6. Give USPS special privileges like the one being discussed... or like the basic monopoly on 'delivering non-urgent letters' that bars UPS from delivering mail into your mailbox.

If all the above sound extremely confused, that's because the USPS has been the object of political meddling for at least 5-6 decades, so it still shows the fingerprints of many ideologically-conflicting schemes and agendas all at once.

The Federal Government really doesn't deal with addresses, roads, etc. That's the job of the states, counties, towns, etc. The USPS, though, needs to know all of that so mail can be delivered.

Via multiple different processes (depending on the entity in charge) the USPS and the entity (state/county/city/town/village/developer/whatever) that comes up with road names/parcels/lots determine the addresses. These addresses get sent to the USPS.

It sounds like the process depends on your specific locality and which government overlays are in charge.

Note that a plat map (the survey that slices land up into chunks) does not necessarily have to include the address.

I lived in a place that was renumbered twice while I lived there, and it wasn't at all obvious - to anyone - as to where the new addresses came from. I asked the county, city, and USPS, and none really could explain how it worked really.

These are all real scenarios I've lived/have family who has lived:

- Town A contains a region called "Village B" with no distinct government structure. However, Village B has its own post office, so a subsection of Town A has a separate ZIP Code and is delivered mail by this second post office.

- Town C contains two disjoint sub-regions (unincorporated villages) called "Village D" and "Village E." Both have post offices and both have their own ZIP Codes. Some addresses in Village D are delivered mail by the post office in Village E—not the one in Village D.

- Town F has its own post office, but a street in town F receives mail delivered by the post office in Town G.

The practical impact of these is twofold:

- Mail is written to addresses not matching the municipal governmental structure of your town/city. - Mapping apps that rely on USPS data to provided addresses (which is generally good, because it means mail will go to the right place) will show the wrong legal town names for the structure.

On older letters, you'll see the red abbreviations instead of the more modern ones:

https://en.wikipedia.org/wiki/List_of_U.S._state_and_territo...

And due to historical inertia, very little has changed since the current (5 digit) system was created 60+ years ago.

https://en.wikipedia.org/wiki/ZIP_Code

you don't really need to know exactly who or where the target house (or IP) is, you just sorta need to know what post office or trucks serve that area (or which networks connect to your target IP / next hop).

thats up to your local post office (or switch) -- send it to them and let them figure it out, which routes and truck to take to get there, like which routes will eventually pass through this locality?

sometimes that's simple and geographical, like a big city and the local post office serves the people around you, 10 miles in any direction, and sometimes it's because there is a mail truck that drives up and down a valley serving people on multiple sides of a state line and in multiple towns.

back in the day, before cars, those routes could be multi-day treks.

also consider that USPS is federal and plays by federal jurisdiction rules, meaning that they don't really care about neat and tidy state or municipal lines -- they're valid everywhere.

tl;dr: USPS cares about delivery routes and that's what ZIP codes help with. These happen to make up, more or less, areas. This is close enough an abstraction for many use cases (which is why they are ubiquitous), but pretty horrible once you get into the details.

https://docs.os.uk/osngd/data-structure/administrative-and-s...

The "city" on my address growing up was a CDP[1], and it is now a city that I live 2 miles from rather than the one that I live less than a mile from.

1: https://en.wikipedia.org/wiki/Census-designated_place

Some zip codes represent a single building. Example 20500 is the White House. The Pentagon is so big it has several zip codes.

https://convene.com/catalyst/office/buildings-new-york-city-...

It used to be that the first 3 digits of a zip code sent that mail to the "main" post office building (the one that has loading docks for like 10-30 tractor trailers on one side of the building). Even if you were mailing a letter to the same zip, it went to that building to be sorted and returned to the local office before delivery. Nowadays, everything goes to central facilities where stuff is scanned and sorted. In Kentucky, almost all mail goes through Louisville.

Whatever you're grouping is likely better served by some grouping based on geography, not based on delivery routes. You probably wouldn't group by telephone company central office either, unless you're telco related.

We want to group by geography, zip codes are easy and vaguely geographic, lets use that is kind of a valid decision, but it's deeply frustrating :p

That's not true: https://news.ycombinator.com/item?id=47619939

Doesn't get rid of all of it, but gets rid of the vast majority, IME.