Zip Code Map of the United States
37 comments
·September 23, 2025mixdup
zip codes are not geographic areas, they are a collection of mail delivery points. Sometimes those points are not geographically contiguous or may overlap
drecoe
ZCTA[0] can (roughly) be used for this purpose
https://www.census.gov/programs-surveys/geography/guidance/g...
paulsmith
This is a fact of ZIP Codes that a lot of people stumble one. I've worked on GIS/mapping projects in the past where stakeholders wanted or assumed ZIP Codes to be polygons.
Another complexity that surprises folks is you can't guarantee a one-to-many state-to-ZIP Code relationship. There are several (I forgot offhand how many, I used to have them memorized) that span across state boundaries.
y-c-o-m-b
Yep, this fact eluded me earlier in the year. I was supposed to map out all ZIP codes in the US and color their boundaries based on certain stats we had. We were surprised to find many areas in the US were empty because they didn't have ZIP codes. I did a quick search and found out ZIP codes are driven by mail routes, and that instantly made sense to me, but the product stakeholders were very surprised to learn it.
paulsmith
One thing I just recalled is that if you maintain a small exceptions lookup table (i.e. the ones that span state boundaries), you can use ZIP Codes as a way to uniquely look up a county name.
chromatin
My ZIP code happens to be shared by two separate cities and there are a few websites (Github, I'm looking at you) that will fail the payment, registration, etc. attempt if you don't enter the municipality that it THINKS is correct.
dfxm12
Would ZIP+4 help here?
voxadam
Related:
Stop Using Zip Codes for Geospatial Analysis (2019) - 184 points, 131 comments - https://news.ycombinator.com/item?id=42974728
pseudosavant
For those that may be interested, this is my project to easily get a list of every zipcode + city/state combo. It is available as JSON you can easily directly work with, or even try a service like this: https://usps-zip-codes.deno.dev/90210.
I have a pet peeve for having to enter my zip code after I've already had to type in the city and state. There wasn't any easily downloadable file that had every ZIP code though. I keep hoping more sites will ask for ZIP first and then just auto fill it using data like this. /wishfulthinking
uptown
Your list is very incomplete. It seems to be missing all zip codes with a leading zero.
dfxm12
I have a pet peeve for having to enter my zip code after I've already had to type in the city and state. What else would you expect? Typing my zip is way easier than going through a list of zipcodes in a dropdown, many of which will be off by one digit in different spots. (ETA: I reread your comment and see what you are expecting)
I like the experience of autocomplete while I'm typing out my street address.
pseudosavant
I like the autocomplete too. Probably the best pattern, but it does usually do that by leveraging paid Google Maps APIs I believe.
I was frustrated that this seemingly open data wasn't openly available. Anything that asks for city+state+zipcode can ask for zip code first, auto populate the rest. For the edge cases where the city is wrong, the person can still type in the city like they would have needed to anyway.
It is worth noting that a package would never get delivered to the wrong place because the city wasn't correct but the ZIP code was. The USPS routes based on ZIP codes, not city/state.
boilerupnc
I think the sentiment for the pet peeve is commentary on the perceived inefficient sequence of the data input and a hope for reducing the number of fields entered from 3 to 1.
>I have a pet peeve for having to enter my zip code AFTER I've already had to type in the city and state.
The city and state can be derived from the zipcode - so why not simply ask for the zipcode to be typed and then auto-populate the associated city and state.
cwmma
There are multiple zip codes in my state (Massachusetts) that cover multiple towns some examples include 01002 which is Pelham and much of Amherst, 01027 which is both Easthampton and Westhampton (different towns) etc.
dfxm12
The city and state can be derived from the zipcode
A few comments here suggest this isn't true.
If you want to reduce input to one field, the autocomplete based on the street address that I brought up is the best experience I've come across.
null
jayknight
It doesn't contain my zipcode/city combination. My zip code spans across a city line, and the json file only has the OTHER city in it.
pseudosavant
For what it is worth, this is the ZIP code data as according to the USPS. The scripts simply create the JSON file for you by calling the USPS API for every zip code between 00000 and 99999 (plenty of holes in there) and recording the response if there is one.
weinzierl
There are more beautiful ones:
https://www.printmag.com/designer-interviews/paula-scher-map...
floatrock
To make this more than "this is just the xkcd population map joke" https://xkcd.com/1138/ , better title could be "Distribution Search of Zip Codes in the United States".
Point here is to type 0, 1, 2, etc. in the search box to see how zip codes with that prefix are geographically distributed.
I read an interesting story where this distribution comes from the manual mail sorting days... before computer sorting, postal workers could read the first digit and drop it into one of 10 boxes based on what part of the country it was going to, and so on for each additional digit.
Other countries have said "ah f it, it's all computers these days anyways, lets just make all addresses arbitrary random codes with no correlation between code distance and geographic distance. A database lookup at computer speed is a database lookup no matter what."
cramcgrab
It would be nice if the usps would get out of mail delivery and focus on email. Wouldn’t mind a usps email account
cogman10
If you find this interesting and you haven't watched it, Go watch "The hidden pattern in post codes" [1]
serbuvlad
The + button doesn't work on Firefox (143.0.1; Linux; flatpak; x86-64). The - button works and so do other ways of zooming in (scrolling, double click).
llimllib
link to the zip code data is broken too; https://public.opendatasoft.com/explore/assets/us-zip-code-l... 404s
Even when I worked for Medicare I couldn't get the damned post office to give us accurate zip code data! It's terrible geodata but also almost everybody remembers it and most zip codes map to one county, so it was the best UI we found for getting a general area for where a person lived.
joecool1029
broken in mobile safari as well.
mlsu
This just places a dot on top of the centroid(?) of the zip code. Would be better with a shaded area for each zip.
Still cool!
nostrademons
You can get that on Google Maps by searching for [XXXXX zip code].
evanb
This map is a neat visualization but is incomplete so far as there are some missing jurisdictions. Puerto Rico and the Virgin Islands, for example.
pseingatl
The Canal Zone never had a zip code.
madcaptenor
Why not, seeing how it was under US control long enough to get one?
null
Interesting (and also somewhat expected) that it acts as a fairly accurate proxy for population density.