[delayed]

As someone who has worked with geodata quite a lot, that wouldn't be a good idea in terms of resource usage. You are blowing up the size of the dataset by one or two orders of magnitude. Maybe even more. Processing these polygons would be extremely annoying.

I once built an interactive map for some areas in Switzerland with postcodes rendered on it. I had to use a lot of tricks to keep it down to a few hundred KB for just about 5% of Switzerland's area. If I tried to add more areas, I'd have to abandon the approach of rendering polygons directly with Leaflet and move to static, pre-rendered images. Now, if you add 10 or 100 times more points, you would barely be able to render it fast enough on the CPU anymore.

So, nice idea, but the polygons become hard to work with then.

Doesn’t that imply that a ZIP code could change if the route is changed?

Making each able to be a union of multiple enclosed areas would probably also help add an axis of flexibility.

Yeah, I always thought that was a bit of an aCkTcHUuaLly type of point. Okay, okay, it's about routes. But, when you can draw perfectly mutually exclusive convex hulls around the unions of the lots receiving mail for a given zip code, then you can draw zip code polygons.

Yea same, then I realized they're not free either :(

The differences aren't too bad, I diffed [1] the USPS Puerto Rico sample with Census ZTCA 2026 [2]. I think I'll just stick Census, simpler model too for data analysis too, if I assume boundaries never change. :) Interestingly, I also learned ZIP Code™ is also trademarked.

[1] https://geojson.tools/?url=https%3A%2F%2Fgist.githubusercont...

[2] https://www2.census.gov/geo/tiger/TIGER2026/ZCTA520/

wait how can ZIP code boundary lines not be free information, that's totally wild, how do you then even know what ZIP code to use if you can't look it up...

what next paying for knowing street names or house numbers??!??

Congress keeps passing laws to make USPS appear to be as "unprofitable" as possible. Such as pre-funding pensions & healthcare for people who have not been born yet [0]. I suspect the goal is to sell off a "money losing" USPS to some campaign contributor for $1 so that person can reap the $60B in pension funds.

One of the features I would try to add at employers was address correction. The addresses API used to be free (became a paid service in August 2026). If you've ever seen a popup at on an order/address form which says something like "you entered X, but the Post Office recommends Y" (or similar words), then you've seen the results of the address API [1].

Notes:

0 - 2022 changes to the 2006 law let them stop prefunding 75 years ahead of time.

https://www.uspsoig.gov/focus-areas/did-you-know/what-did-po...

> To qualify for regular retirement, employees must have at least 30 years of service and be 55 or older; or 20 years of service and be age 60 or older; or 5 years of service and be age 62 or older.

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

1 - https://developers.usps.com/addressesv3

Apparently it is because the USPS has a special carve out from congress exempting it from disclosure of "information of a commercial nature", subsection (c) here: https://www.law.cornell.edu/uscode/text/39/410

Probably because of the silly idea of quasi-privatization,

> But, beginning in the 1970s, the Postal Service largely stopped receiving any taxpayer money for ongoing operations. Postal operations are instead funded by sales to you, the postal customer. Now it depends almost entirely on sales to keep the lights on.

https://www.uspsoig.gov/focus-areas/did-you-know/postal-serv...

This move roughly aligns with the administration's broader desire to take data generated by the government at taxpayer expense, and hand it over to his buddies to privatize and profit from it. See also weather data.

TIL: USPS makes money with its own budget while USPS get some funding for government programs like rebates.

So yeah, they can sell that data legally.

https://about.usps.com/who/profile/

> he Postal Service generally receives no tax dollars for operating expenses and relies on the sale of postage, products and services to fund its operations

Pretty much every state charges for some data and not others.

The USPS itself is a quasi-government corporation, so it probably functions under a different set of laws. I know that they will sell you a list of all the addresses in the US for a price. I've never thought about doing a FOIA request. You can try?

https://postalpro.usps.com/ZCB_License would seem to prevent such a use/distribution of the data.

There are plenty of 'good enough' options that are free; just ignore the USPS' offerings unless you ABSOLUTELY have to match them 1:1 for business reasons.

Also, there are a few zip codes that cross state boundaries. Those rare cases involve very rural areas where the nearest post office is across the state line.

The +4 bit of the zip code narrows the location down to a block or street. In the case of apartment/condo buildings, each bank of mailboxes (for each lock that the mail carrier uses) gets their very own +4.

Sample picture: https://postalsupply.net/2023/03/maintenance-and-upkeep-tips...

I’m just learning about this from the comments here.

Do you know of anywhere I can learn more about why this is?

Have they ever thought about changing it so a “postal code” IS a geographical region?

Fun fact, a postcode can represent up to 100 addresses, apartment buildings with more than 100 units have multiple postcodes. Sometimes third-party systems will only recognize a subset of those postcodes (e.g: a system might assume a building only has 1 postcode) which can lead to some residents being in the geographic region for a service while others are not despite being in the same building.

Also postcode data is licensed by the Royal Mail, not free.

As someone from the Netherlands I’ve been very surprised at how far “ahead” we seem to be here. Just a postcode can point you to a street, even the side of the street (right or left hand), a house number than gives you the exact building. That is how people are used to enter their address here.

When I had to work with addresses in other countries, I found out that is not that normal.

Interestingly, there are no polygons for UK postcodes, because UK postcodes don’t represent a geographical area; instead, they represent one or more discrete points.

"A full postcode identifies a group of addresses (typically around ten) or a major delivery point."

The United States can be more granular, as a "full postcode" equivalent in the United States is ZIP+4, which can resolve down to an individual building, mailbox, or person, depending on the characteristics of the location.

https://en.wikipedia.org/wiki/ZIP_Code#ZIP+4

most people dont know that zip codes are specific to the postal service and dont have anything to do with actual municipal government boundaries. the hierarchy of geo boundaries and the ways to locate and communicate within them is way more interesting than one would believe!

Polygons do have value in some workflows, if used with the appropriate caveats.

And in no instances have I ever run across use cases where these are worth paying any substantial money for. If USPS is going to jump into the fray here, really bad look (and probably net negative revenue for them) to offer as a paid product.

This. The USPS has always said that a ZIP Code was not a geographical area, but a collection of deliverable addresses. So what is this nonsense?

As someone who did a little geospatial work, I concur. We had banks complain that we didn't have ZIP codes for some ATM locations.

The ATMs never got mail.

I assume you're asking this question in good faith. A mailing address alone is often ambiguous, eg tons of duplicate street names, people write the wrong city, and typos and missing unit numbers are common. The ZIP code doubles as a sanity check against the rest of the address. USPS will usually figure it out without one, but it takes extra time and effort. Also, a person's zip code also doubles as card verification and sales tax. Maybe the opposite question should be asked, why do we need addresses? Your residence could be defined expanding on its zip code.

It made a lot of sense in the pre-internet days. Getting a human to sort mail without looking up a big list was pretty useful.

Property lines are a whole other rabbit hole USPS has nothing to do with. Property lines are maintained by county/parish/... (GIS) departments and a few companies managed to aggregate them all. And they are famously inaccurate. "GIS" stands for "Get it surveyed"...

Wow. That's some terrible behavior. In the US you can't copyright simple facts (such as "this lat/long has this postal code"). But by that logic, it's hard for me to see how USPS can lay claim to the dataset being discussed here either, but I assume they have attorneys who told them why they can.

Is that the real pricing?

The US Constitution requires them to exist. Congress keeps passing laws screwing with their operation. Such as requiring pre-paid funding pensions/healthcare for people who have not been born yet.

> they can't declare bankruptcy

According to Amendment 14, section 4:

> The validity of the public debt of the United States, authorized by law, including debts incurred for payment of pensions and bounties for services in suppressing insurrection or rebellion, shall not be questioned.

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

According to that clause, especially the bit with the comma, Congress & courts have held that government bodies cannot discharge debts in bankruptcy. They go through Chapter 9 of the bankruptcy code. Every other chapter in BK allows for some debts to be wiped away.

Huge.info has existed for decades:

https://maps.huge.info/zip.htm

Structural changes are required for then USPS to be financially stable. Chief among them is modifying the Universal Service Obligation (USO).

For far too long, private shipping/logistics firms like UPS & FedEx unfairly take advantage of the requirement by the USPS to deliver mail six days a week to over 160 million addresses at uniform, affordable rates. UPS/FedEx will receive the package and do the long haul. But then instead of driving the package to a final residential doorstep themselves (incurring high residential and fuel surcharges), they drop it off at a local USPS branch or regional hub. USPS letter carriers complete the final-mile delivery to the recipient's home or P.O. Box. It's literally part of their business model. UPS calls it 'UPS Ground Saver' and FedEx calls it 'FedEx Ground Economy'.

These hybrid services typically cost 20% to 40% less than standard UPS Ground or FedEx Ground. It takes longer to ship but UPS/FedEx bypass the steep residential delivery fees (often $6.45–$6.50+ per package) that private carriers charge for dropping off at houses rather than businesses. Also, it's the only way to deliver to PO Boxes because standard UPS and FedEx ground services don't do directly.

This is classic example of capitalism where private companies 'keep profits and socialize losses'. The 5% annual dividend paid by FedEx every year to shareholders is paid for by American tax-payers funding the last-mile delivery of packages at dirt cheap rates.

The USPS is losing money hand over fist delivering the unwanted junk mail

The fact that you think the Postal Service loses money delivering junk mail shows that you don't have any idea what's going on.

Junk mail is a massive revenue source for the USPS. According to the congressmen I've spoken with (Yes, I actually have done that), junk mail is hugely revenue positive, which is why it's allowed to continue.

USPS' financial problems largely have to do with pensions and other non-delivery issues.

https://www.gao.gov/blog/us-postal-service-losing-money-what...

blame EDDM, aka junk mail, aka physical SPAM that you can not opt out of. its a jobs program that I suppose also benefits the paper product recycling industry

i have a hole in my pool... thousands of gallons per day are draining into the neighbors yard

oh, so are you having someone come out to patch the hole and fix it?

no, the hole is still there. we are spending 3k per month to get a water delivery truck to refill the pool.

this data has been monetized for decades

Try is the key word. It won't work.